Imperial Home Page -> Repair -> Electrical System ->Dash Lighting -> Incandescent Bulbs
Tip from Jay:
Some of the dash bulbs have leads and some twist into the back of your dash and use a circuit board for electrical connectivity. If you are removing your dash, be sure to disconnect the leaded bulbs. Another good idea is to label them so it will be easier to replace them.
Tip from Chris:
If your dash lights do not work, first check to see if all the dash bulbs are burned out. They will either unplug from the back of the instrument cluster and make contact only through the printed circuit and/or the bulbs will have wires attached to the bulbs that need to be disconnected.
Tip from Mark (1969):
The bulbs used to illuminate a '69 dash are not out of production - I just bought a half dozen. They are small, very ordinary GE #1816s (same # under different manufacturers).
Tip from Chris:
To replace bulbs in a dash, I cheat with a spare '65 instrument panel that I study to see where various light bulbs go. Then I blindly reach up from below the dash to the general area I know the faulty bulb SHOULD be located. Unscrew 1/2 turn to remove bulb holder, replace bulb and reinstall. Without this guide it is pretty hit and miss, but there is no simpler method I'm aware of.
Tip from Kerry and Dick - Making a tool to replace a VOM (Volt-Ohmmeter):
I have build a test light 'tool' to have on hand. I made one long leads with a large 'alligator' or similar clamps so I can connect one to the battery post and the disconnected battery connector. The leads will be long enough so I can pull the bulb into the interior while I am pulling fuses. The bulb needs to be small enough to be lit by the size current drain you are looking for. In the case of a battery going dead in two or three days, this would certainly work, as that drain would have to be of the order of an amp or more, and the test light bulb needs only 1/4 amp to work. One would connect the test light in series with the + cable.
Follow-up by Dick:
I need to know the candlepower or the wattage of the bulb you propose to use. The smallest wattage you can find and still see the light is best. If the wattage is too high for the current leakage you are trying to find, the bulb just won't light, no damage will be done.
If you have a battery that is taking a couple of weeks to go dead, you are probably not going to be able to find a small enough bulb - a VOM is the only way to go in this case, as it will give you an indication on a current leakage of only hundredths of an AMP. (This statement is corrected below, read on.)
To get some estimate of the current we are talking about here, use the following equations: (don't panic now guys!)
Take a typical 12 volt car battery with an energy storage capacity of 80 Ampere hours. This number means that the battery can deliver 80 amperes for 1 hour, or 40 amperes for 2 hours, or 20 amperes for 4 hours - in other words, the current drain multiplied by the time equals the drain from the battery. A x H= 80, in this case. Note: we are not talking about CCA ratings here, that's a much different parameter, which has significance primarily in cranking a cold engine.
So for a car's battery to be drained to the point where it won't start the car, lets say the energy is 80% drained out. This would mean the leakage current has stolen and wasted 80% of 80 Ampere Hours, or 64 AH. If it takes 64 hours for this to happen, there must be a 1 AMP drain going on here. If it takes 128 hours, it must have a 1/2 AMP drain. If it takes several weeks, lets say 3 weeks or 500 hours, it would take only a little over a tenth of an AMP, and so forth.
Now, regarding your test light idea: The typical small regular base #57 or 1895 bulb is about a 3 CP bulb, and for our inexact calculations here, trust me that this is around a 2 watt bulb. Wattage of a bulb (or anything else in DC current) is the product of its operating voltage times its current. VxA=W, in shorthand. So for your 2 watt bulb, 12xA=2, A=1/6 AMP or 0.167 A indicated on your VOM. If your current drain is more than this, the bulb will glow at design brightness, and no damage will be done, since the current is self limited in the bulb.
If the drain you are looking for is more than that 0.167 A, the bulb will light your way to the culprit. If the drain is less, the bulb will glow dimmer, until you can no longer discern it for very slow drains, but I'd guess you can still use it for drains of 0.1 A, although it will glow pretty feeble, you will be able to see it.
So yes, now I conclude you can use a #57 bulb to do exactly what you propose, and it will work for you.
Question from Denis (1958):
The rheostat part of the headlight switch, which governs the dash lights spins around not doing a thing. I bought a nice looking used one from Lowell Howe, but the mechanic doesn't know how to make it work. Is this thing connected to elector luminescence, or something? Any info on how to get the dash lights on the 58 Imperial working for the first time will be appreciated.
First I hope that you have a '58 rheostat and not a '57: there are differences between the two, '57 is a "two cases" rheostat / switches-breakers, '58 has components in an only one case. Another difference is that you couldn't put a '58 in a '57 dash, as casting of the dash at this location is different. It's invisible if you don't see the rear of the dash. I have a '58 headlight switch but I couldn't use it in my dash (or I would use the '58 dash which has the rearview mirror at a different place..). I look at my '58 rheostat on the table just under my eyes and I see at the rear of it: - at center of it, 2 pins: BAT and AUX; the BAT (red wire) goes to ignition switch then to + 12 through ammeter. The AUX 3 pins assy. goes to pink wires (accessories as map light, stop light switch, glove box light). There's a circuit breaker inside between these two pins. - on the exterior: 5 pins: P , IG, H, I and T
P = parking light (yellow wire)
IG = ? but always connected to
P H = headlight foot dimmer switch (wire green).
I = Instrument lights (orange wires for inst. lights, the ones you need). It's a 3 pins assy.
T = taillight (black wire).
With an ohmmeter you could verify that : - position 1 (off): you have a short circuit between Bat and Aux, no connections with the others - position 2 (parking lights): you have a short between Bat, Aux, P, IG , I (or some resistance depending of the outer axle which commands the rheostat) and T . - position 3 (headlights): you have a short between bat, Aux, I (same remark than 2), H and T.
If you have the outer axle at the extreme left, the instrument lights are off. On my '58 switch the rheostat is not very reliable as on my '57. I was lucky to find one in perfect condition on a '57 wrecked Crown I have! If the rheostat doesn't work you could have illuminations of instrument lights if you connect the orange wires to the "T" pin.
I am trying to crank up my memory so there are "'if's" in this. I remember that some cars of that period had the dash bulbs in series. So if one burnt out the rest did not work in the system. Take the bulbs out and test to make sure that they are not burnt out.
That was the easy part. The rest would be to test for power from the inbound power source and test the wires to each socket. I don't remember if that period if Imperial used circuit boards. If so, then there is possible corrosion, where the bulb socket snaps in or a sloppy fit.
Question from Marty (1959):
Are there any special tips on replacing the bulbs in the dash of my '59 Imperial? What kind of bulbs does it take? And where can I get them?
There are four bulbs for the dash lights. They are #57 and they are an in stock item at our local discount parts place. You should be able to get to them by standing on your head and running your hand under the dash. If not you can pull the whole instrument panel pretty easy. I can scan that page of the FSM and send it to you if it would help. Pull one out and I believe you will find.
Try "Bulb Direct" at 1-800-772-5267.
Question from Rex (1959):
The gear shift indicator buttons will not really illuminate on my dash board. I have, of course, checked and changed the bulb and know it's working. I have removed and cleaned the buttons to get the white film that forms on the old plastic off. Still, despite my best efforts the buttons have only the very faintest illumination. On the other hand the heat/ac buttons glow rather brightly. Has anyone else had this problem and can you correct it? And while we are on the subject of '59's my turn signal indicators also glow slightly whether the turn signal is on or not. This is true of both sides.
The turn signal glow is probably from light reflection inside the gauge assembly. Some older model cars use paper tubes to separate light sources. Some have paper gaskets in between the gauge case and the dash pot. If one of these items are bad or out of alignment light will leak in.
I have the same problem on my '57! First the green clear plastic becomes darker with age, second the small bulb doesn't help to illuminate the end of buttons. If the "light conductor" (a polygonal piece of clear plastic or glass enclosed in the bulb swivel assembly) is dirty the light can't go to the side of the button. With my poor original buttons, there was no light at the end. I've put much "newer" (NOS) buttons in but I also added another bulb (on the other side of the buttons) when the dash was out of the car. It's better but some buttons are less "lit" than others.
Sounds like a ground problem. Check any place where a wire or cable bolts directly to the body or frame. I think you will find one that is loose and rusted or maybe where the battery ground bolts to the body. This will cause the power from the lights to "feed back" through any other system it can to find a ground. This probably is the same trouble as the shift button illumination. Try a short wire, grounded to the body and then touch the other end to the side of the turn signal bulb/socket. Check all the turn/tail light bulbs for proper bulbs.
Question from Terry (1964):
On my '64, the gauge readings all seem to oscillate up and down together. Voltage regulator?? Something worse?
Most likely a poor ground to the cluster. Try tightening all the mounting screws that fasten the gauge cluster to the dash metal, and if that doesn't help, add a wire from a screw on the metal housing of the gauge cluster to a known good ground, like the dashboard. Be sure to clean everything down to bright metal.
This is caused by the 5 volt power supply for the gages. The ammeter should not be affected. Often you can carefully dress the contacts in the regulator if it is accessible. Otherwise a new regulator is required. I do not know a source for these offhand.
I had this problem on a '68 a long time ago. The fix was a small plug in unit on the back of the instrument cluster called a voltage limiter, it resembles the turn signal can, but is smaller and rectangular, with two blades. Also it is a mechanical not electronic unit.
Question from Alan (1965):
I have a '65 LeBaron that has flickering headlights/ dash lights. Any thoughts?
Replace the points-type voltage regulator with a solid state regulator. Year One (http://www.yearone.com/) has a solid state regulator that's an exact replacement, looks just like the original, and only costs about $10.
Had the same problem on my '63 Catalina wagon that I bought last fall. Turned out to be a bad headlight switch.
Without seeing it , it sounds typical of a bad regulator. Even "new" ones can be bad.
Question from Wayne (1966):
I need to replace the ammeter on my 66 Imperial. I have a used one to install, but the indicator "needle" on my used gauge is very faded. Is their a paint available that I could use to renew the color on the gauge needle?
A good model shop should have the sort of paint that you require
Testors Model Master Fluorescent Red FS28915. Find it at a hobby shop that sells model airplanes and such. It's a perfect match.
I did all four gauge needles on our '62 using the Testors fluorescent orange. I think some have called it a "red" but I just found a good match to the speedometer drum.
You shouldn't have trouble with the glowing of your gauge needles after they are painted if you don't put the paint on too thick.
If you have a good quality small modeler's paintbrush and steady hands you should be fine. Use fresh paint (not partially dried up) and take an even stroke from the base of the needle to the tip. Rotate the needle a little bit and take a second stroke to get good coverage. Two even strokes should be all you need. The key to getting a thin and even layer of paint is to keep the brush moving and don't do any "touch-ups." Doing touch-ups or going over the needle with more than one coat will make the needle appear blotchy or slightly darker than desired when the needles are glowing.
Question from Gary (1966):
I have a 1966 Imperial Crown Coupe. I was on my home from work tonight a funny thing happened, my instrument panel went dark and my map light came on, and would not shut off. When I put the lights out the map light went out. If I put my flashers on and put the light on then put my foot on the brakes the instrument panel light flash on and off along with the map light. When I turn the light switch to the left the back lights on the inside of the car come on very dim. Any ideas what the problem is?
As complicated as it may look, I bet you have just one wire touching something it shouldn't. Similar things have happened to me when hooking up tail lights and such when I mixed up the common and the hot wires. Electricity flows in a different path through the bulbs and causes them to become resistors. Check all of your connections under the dash and look for anywhere the insulation might be worn off a bundle of wires. Good luck.
This will take some sorting out. I suspect the problem is right at or very near your headlight switch. I do not have a 66 so I don't know how much trouble it is to take the headlight switch down so you can inspect the wiring, maybe it is easier to slither under the dash with a flashlight and a dentist mirror. Anyway, what you are looking for is the wire that feeds your instrument illumination bulbs (probably a black #18 wire) has melted through and come in contact with the map and courtesy light circuit, probably where it drapes over the top of the headlight switch. The headlight switch has a rheostat which gets very hot especially if you were running your dash lights around the mid brightness setting, if a wire came in contact with this area, it would melt through sooner or later, and cause all kinds of potential symptoms, some of which you are seeing.
If you need advice on removing the headlight switch, I can help some, but someone with a 66 would know exactly how to hold your left earlobe while you are fishing for the release button on top of the switch.
Question from Don (1967):
The dash lights on my '67 work very dimly at only one setting of the rheostat. Is this situation fixable or do I need to find a new switch?
Every time I have had that issue it has been due to corrosion or a worn out headlight switch. Pull it out and clean it up.
Try cleaning the rheostat with tuner bath or alcohol and also check the wires going to it in case one might be breaking. If it is in fact a rheostat, and not a rotary switch, it should very the resistance from high to low in a linear fashion, like from 0 to 100 ohms for example. The easiest way to check is with an ohmmeter between the slider and one of the outer connections while moving the knob back and forth. With regard to the position of the knob, do the lights come on when it reaches the end or do they come on in the middle someplace? Hopefully the reason that it doesn't work if from dirt and disuse and not wear.
Stupid as this is going to sound, the first thing to do is on of the easiest, barring the wear on your thumb.
Background: the rheostat is simply a moving contact point sitting on a resistor block. Turning the thumbwheel moves it along the block, increasing or decreasing the resistance and effectively changing the intensity of your dash lighting.
The usual problem: The resistor block gets cruddy, and/or the contact point gets dirty, mostly from sitting in one place all the time.
The easy solution: Move the thumbwheel on the dash (the adjuster control) back and forth about 100 times (seriously). Well, maybe try 20 or so first and see how you do. By doing this, you clean the contact point and where it touches the resistor.
The good news: This usually works! And if it doesn't, *then* take apart your dash and get at the switch.
Question from Don:
Last night on my way home from a Cruise, my dash lights would not work, I adjusted the "panel" switch to no avail. Additionally, I discovered that I had no tail/license plate lights. After a while of fiddling with the "panel" switch I managed to get dash lights, as well as tail/license plate lights!!! Are the two connected some how? Or do I have a problem that needs some immediate attention? Until last night I've not had any problem with either.
The taillights and the dash lights are on the same fuse. Try replacing the fuse, even if not bad, as a way to reestablish the circuit contacting points.
Follow-up from Don:
I did replace the fuse - and removed and cleaned the headlight switch and all connectors - and all the taillight bulbs. Dash and taillights worked briefly, then mysteriously quit again. I have another headlight switch I got from Murray Park, but taking apart the dash is such a pain I've avoided it.
Reply from PEN:
Start looking for a bad ground wire. Start with the ground wire on the back right side of the engine, going from the engine to the body. If that is not in contact, then the only other route for the juice to run would be up through the speedometer cable, creating a lot of resistance, and making everything run wrong, if at all.
Question from Anthony (1967):
When you step on the brakes ---dash lights and running lights and turn signal fender lights up! Has anyone experienced this sort of problem before! I am visiting my mechanic again tomorrow---he is thinking there is some sort of grounding problem some where! Initially, he thought it may be a faulty turn signal switch---however----when the car is off and you depress the brakes, that is when the dash and running lights illuminate.
This is a very common issue with an easy solution. There may be a shorted bulb or pigtail probably in the Stop/Tail combo cct. Replace the bulbs in the rear of the car for starters then if that doesn't work, test all pigtails for continuity/shorts.
Have you checked your fuses? I had a blown fuse on my 76 that caused the dome light to come on when I pressed the brake pedal. It caused me much confusion too, hehe!
This sound like a bad ground at the tail lights. I have chased these a couple of times in the past. If your brake lights are dim it's the ground. If they are bright it's Brad's short.
Reply from John:
The tail lights should be evenly bright when not stepping on the brake. If any are too bright, you may have the wrong bulbs in some of them.
I'd start by checking all fuses. I've had strange lighting situations with a blown fuse in a '63. I would also check for pinched wires to tail lights & any wires near the brake pedal. Have you recently replaced any bulbs? If yes, are you sure they are the correct type? Is the turn signal switch a generic replacement or Mopar & is it wired correctly?
I agree with Craig, sounds like a ground problem.
Question from Mike (1967):
The dash lights on both of my '67 Imperials don't work. I suspect the rheostat switch is the culprit. Has anyone tried to repair one of these? Or does anyone know of a rebuilding service for these?
A short is a connection from hot to ground, not from hot to load. Other than that, the idea would work in theory. In practice, the sweep on the rheostat is intended to make contact with the lead at the counterclockwise position anyway.
You should try JC Restorations. They are very good!!
The little thumbwheel on the dash? Take your thumb. Rotate the wheel all the way to the right. Then all the way to the left. Do this until your thumb is sore. Then switch to your index finger. Continue on down the line until one hand is sore and calloused. Then switch to the other hand.
At some point in all this masochism (provided your battery is hooked up and the bulbs are OK) you should begin to see a flicker of light. Eventually you will get the lights working well on one brightness setting. If you have tough hands, you may get them working on a few different settings.
Some expensive electrical cleaning solution doused on the switch before-hand and during the process may expedite things somewhat.
Follow-up from John:
I agree with this solution, but never found I had to wear both hands out to make it work. There's usually a lot of buildup on the contacts that will wear through after moving the switch enough times. Same goes for the earlier Imps with EL lighting. If you can hear the faint hum of the power pak when the dash lights are turned on, this will often get those working also
Question from Bob (1968):
I am working on a '68 Imperial convertible. On the dash there is a red light that is on when I turn on the key it was not on before I dismantled the car. It is on the left of the fuel gage. I have not put fuel in it yet do these cars have a low fuel light.
If the lamp is to the LEFT of the fuel gauge, and is just a round lamp with no lettering or symbol, this is the high-beam indicator for the headlamps.
The "CHECK GAGES" lamp (spelled just like that) is to the right of the fuel gauge, pretty much under the "0" in the speedometer.
Why your high beam indicator is on whenever the key is on eludes me. It should illuminate only when the high-beam headlamps are on, regardless of ignition key position. Sounds like there is a short to some ground somewhere, perhaps near the instrument cluster? Are the headlamps glowing all the time??
Dick is 75% correct (25% less than usual) about the operation of the Check Gages light... it tells you to look at three of the four gauges for signs of improper oil pressure, low fuel or high temperature. It does not monitor the alternator gauge (ammeter).
The third and final indicator lamp in the cluster is at the opposite end of the speedometer from Check Gages... it says "Brake System" and warns only of low brake fluid pressure. It does not indicate an applied parking brake.
That's all there is for indicators in a '67-68... there are not even turn signal indicators inside the cabin!
Follow-up from Bob:
The light is in between the oil pressure and the fuel gage. I do not have the head lights back in yet the car has to go back to the paint shop as soon as I have it back together and running on it's own power.
Reply from Chris:
Yep, that's the high beam indicator.
Perhaps the missing headlamps are causing it to light up in search of a ground... See what happens once you re-connect the headlamps (simple enough to do temporarily even before the car is done... just plug 'em all without installing them).
If its the same as my '67, the red light on the dash signals that the high beams are engaged...the low fuel indication is signaled by the "check gauges" light, and the brake warning light says "check brakes" or something similar.
Question from Trevor (1968):
I think the light bulb that illuminates the control panel in my 68 Imp Crown convertible is out. Before I get in there and pull the entire dash off, does anyone know the CORRECT way to get to the bulb for replacement.
It is not clear from your post whether you mean an individual bulb or all the bulbs are out thus rendering your total dash dark. If the latter is the case, the most likely culprit is not the bulb(s) but the panel dimmer switch that interacts with the headlight switch. Its the serrated or coin edged wheel to the right of the headlight switch. Try rapidly moving it back and forth about 1,000 times, that will create a clean contact area on the rheostat and may restore your light function. I would do this in the dark so you can see possible glimmers of light return momentarily to the dash as you do it and know that it is the source of the problem.
I am not sure what you mean by "control panel," but I will assume it's one of the light bulbs on the back of the instrument cluster or the shift indicator. All can be accessed without removing the dash provided you are limber and patient. Having three elbows in one arm helps but is not necessary.
The bulbs are installed in little holders that screw in without wires into holes in the back of the cluster assembly. I believe there are six in total. There is a printed circuit board affixed to the back of the cluster by which the bulbs make contact. If you can see behind the dash via the footwell (use a good flashlight), you'll see a number of small black bulb holder scattered here and there around the back of the cluster. You should be able to locate which one is which, as they are direct-illuminating (and therefore right behind whatever part of the cluster they are supposed to light up).
The bulbs are size #57.
If you are talking about dash illumination, there are many light bulbs. If they are all out at once, including the one on the driver's armrest and the one in the radio, you have the old malady of crud on the rheostat! Check the archives for a long discussion of this, but the short version is that you need to turn on your lights (parking lights will do) and operate the rheostat throughout its range a multitude of times. Do this at night so you can see the dash lights flicker as you begin to wear away the accumulated oxide. Keep it up until you get full brightness again. You will have a blister on your finger, but the good news is that you only need to do this about once a year to keep them going.
The new number 1895 bulbs are the same specs electrically as the old 57's, but seem to be much longer life, and are readily available.
However, the chances of all 9 bulbs (I think that's the total) going out at once is quite a stretch, I rather think its a power supply problem.
Question from Mark (1968):
I am almost through with restoring the dash and the other bronze pieces on my '68 convertible - and I did it without putting a bullet in my brain, though I was tempted a few times . . . more on that later, BUT--
I had to drop the steering column in order to get to the bronze around the instrument cluster. In order to do that - as a safety precaution - I disconnected the battery by removing the ground/negative cable.
Okay, after I finished with the dash and put everything back together, I reconnected the battery and . . . everything worked. This in itself was a surprise, given MY luck, but what has happened is, the 2 rear seat "courtesy lamps" (I think that's what they're called - they are in each armrest and illuminate the seat & floor area in back) now stay on ALL THE TIME.
Even when the car is off and the key is not in the ignition. They are supposed to only come on when the door opens, I think. What have I done? Did I screw up the wiring under the dash somehow?
To "solve" this problem, because I was dead tired, I just removed the bulbs. Doing this, I noticed that these things got hot as firecrackers and seemed to be burning REALLY BRIGHT, as if they were getting a lot more juice than they should.
Anybody got a clue? I'd like to have working courtesy lights.
One other thing. I've noticed that this car has a peculiar "feature" in that everything electrical, like the windows, works even when the car is not turned on or on "ACC." Most other Imperials I've seen, you have to turn the key to let a window down, etc. But this is the way the car has been since I got it.
Something is not right with your car. If you have the electrical diagrams, you should be able to track down where someone had miswired something.
As for your courtesy lights, did you check that you had not moved the dash light rheostat all the way past bright to where it brings on the courtesy lights?
And did you check to see that your door jamb switches are still mounted properly, no loose or touching metal at their contacts?
If so, and your problem is not solved with the courtesy lights, I haven't a clue, you'll have to start pulling fuses one by one until you find which circuit is supplying power to them and track down the wrong connection.
The extra heat from the bulb is normal, there is only 12-volts available in the car, nothing higher, and the bulbs are supposed to run on 12 volts, that is all it is possible for them to be getting. They do run hot, they are high power bulbs. They are not designed to be on for long periods, in fact on many cars the lenses are yellowed from overheating due to someone leaving them on too long.
Definitely check out Dick's suggestions and figure out why the lamps stay on (does the front map lamp under the dash also stay on, or is it just the pocket lamps on the front seatbacks?).
As for the lamps seeming really bright, check that the correct bulbs are installed. They should be a #90 type. If someone once installed a higher- wattage bulb, that would be your problem. But as for bulbs being hot and seeming brighter when you remove a 30-year-old diffuser lens (especially at night), this is not too far from normal and might just be your perception of the bare bulb. And bulbs do get hot, but they shouldn't melt the lens...
As for "everything" working with the key off, yes, nearly everything should. It is normal on 67-68s for the power windows to operate regardless of the key being in the car. Ditto the power antenna, the power seats and all lights except the turn signals. (The front cornering lights will illuminate if you put the turn signal switch in either "on" positions as long as the parking or headlamps are on, though the turn signals themselves will not light.) Of course the power door locks work without the key on. And the trunk release is not electrical, so it works any time.
But just about everything else (radio, wipers, heater fan... gee, that's about all!) should shut off when you turn off the key.
Follow-up from Mark:
I know bulbs are supposed to be hot, but this was ridiculous. The housing itself was burning hot to the touch. Even with a doubled over rag, the housing of the bulb was hot as hell. This worried me, but I think Dick's suggestion was probably right - these bulbs are not meant to be on continuously, and they had been for about 2 hours at that point. My first thing to check will be the switch, cause I did move that a lot while cleaning the dash.
Question from Leo (1969):
Is there a secret to getting access to the instrument lights on a '69 to change a burnt bulb?
If you can't reach the bulbs (which would involve laying on your back and twisting your body into the most contorted positions that are humanly possible), your only choice is to pull the instrument cluster. There are directions in the manual for this procedure, and they're fairly accurate.
I've had the pleasure of removing and reinstalling the dash on a '70 T & C. The "C" bodies used the same lighting. The lights are mounted up in the "hooded" section of the dash and shine down on the instruments like floodlights.
Question from Kenyon (1973):
My "Brake System" idiot light came on. I was able to make it go away 3 times in 40 minutes of stop & go by poking the pedal, but it returned 10 minutes later and then went out in useage.
What does this light measure and warn of?
The pedal feels a little mushy, and I can get it all the way to the stop when the car is in neutral and stopped, but works fine otherwise. Mushy pedal might be my imagination, as I don't drive the car as often as I should lately. New booster by me, and supposedly new MC, fluid, & pads (the last three by previous owner reported to me by word of mouth).
Fluid level appears acceptable.
What should I check?
The "Brake System" light comes on to warn you of low pressure in the lines.
In my experience, when this light starts flickering on and off, you've either got a bad master cylinder, leaking brake line/hose (the rubber hoses to the front calipers are most susceptible), or bad rear wheel cylinder.
You mentioned that you've replace the master cylinder. Was it new or rebuilt? I've had premature failure from rebuilt units. And if the fluid level is staying the same, a failed master cylinder would be a likely culprit.
The light is telling you that there is a pressure difference between the two circuits. Check your fluid levels and see if one of the reservoirs is low. If they are both full I would then suspect that you have a stray air bubble floating around in there somewhere.
Question from George (1981-1983):
Six months after I bought my new 81, the cluster failed and was replaced under warranty. Five years later the second one failed and I paid something like $500 for its replacement. I asked for the bad cluster, found a loose connection and got it working. A few years later I hooked it up on my workbench, put a speed sensor in my drill press, rigged up a box with a bunch of little pushbuttons to simulate those on the dash and happily put some mileage on the display while I worked with other things. Eventually the displays went black and I put it aside for ten years. Now I am trying to find out why it is dead. I don't see any fuses although there are two black knob-like things that come out with a quarter turn and appear to be holders for very tiny glass tube type fuses. Both are empty and I am sure I never removed fuses from them. There is another cavity for one of the knob-things but it does not even have a knob-thing in it. Does anyone know what is going on with these holders and before I start trying to trace the power flow on the circuit board is there a schematic available anywhere?
Reply from Dick:
I don't think anyone outside of Chrysler has ever discovered the schematic. There is a connection diagram in the service manual, and you can hook the cluster up to power (as you undoubtedly did on your bench years ago) and operate it easily. See page 8-419 of the main manual.
The black plastic removable items are the bulb sockets for the various warning lights on the dash. Perhaps you removed the bulbs (#194s) to use on something else? If you shine a flashlight through the empty holes, you'll see the various warning messages or symbols light up through the front. I'm sure there is no connection between these missing items and your cluster's refusal to operate.
Are you sure you are providing +12 to pins #1 and 3, and ground to pin 2? Also make sure you are not resting the cluster on it's base, thus depressing the "self test" plunger that protrudes from the underside of the case. It's OK to push this plunger, but it will set the cluster off on its little routine of sequencing through all the segments of the display. Illuminating, but not very satisfying!
Question from Lance:
None of my gages work, the dash looks a little loose and the panel under the steering column is off so I am assuming something got loose with the last owner. The check gauges light is on.
I have the same problem with the gauges on my convertible. There seems to be a loose connection on the ignition switch. When I wiggle the key a bit, the gauges work again.
Take a look at the schematic in the 66 FSM. You should be able to identify the wire(s) that are causing your problem. Note that if your ammeter is involved the car may not run, so I would advise you to identify and solve the problem.
Question from Rhett:
When I activate the turn signals, I only see the left one flash on the fender tip...and see neither indicated anywhere on the dash. Did Chrysler just stick with the external indicators on the Imperial and ditch the instrument panel units?
Reply from Kerry:
No flash indicators on the dash. I had the same problem. Check all your bulbs and finally change the flasher. Its hard to find but my web site describes where it is. http://dte.net/57imperial/73saga/73Part16.htm
Tips and Question from Ed (1981-1983):
Today, I removed the upper and lower instrument panel bezels to gain access under the dash. First I replaced my Climate Control head, which was in bad shape, with the one I got from Wayne, and it looks like new. Of course, these jobs NEVER do seem to go easily: I manage to pull all of the vacuum control lines out of the back of the connection, and so had to get out the manual to figure out which color went in which port.
I also replaced the alarm system control box. I installed an AS-600 alarm several years ago, and the processor failed recently. The company replaced the brains and both key fob remotes, and now it works fine again. Ahhh... to have power door locks again.. You see, the alarm locks/unlocks the doors, but with the module removed, the power locks became inoperative. How low-class to have to reach all the way back there and manually lock the doors in an Imperial!!!
Next I removed the power antenna/intermittent wipe modules to get to the headlight switch. The rheostat on mine never did properly dim the dash display; it would go from full bright, just begin to dim, and then out. So I cleaned up the rheostat and even placed a shim on the contact to make sure it was staying in touch with the rheostat. Still, this failed to help. So I found, to my surprise, that I could get a NEW(!) headlight switch (Wells SW189) at Discount Auto parts. All I needed to do was remove the attaching bracket from my old switch, attach it to the new one and install. It now works perfectly.
Unfortunately, I was not so lucky with the next part of the job. A few months ago I replaced the wiper motor with a rebuilt one from Auto Zone. The old motor would "stall out" when operated on high speed, as if it was popping the circuit breaker; the wiper would stop, seemingly the c/b would then reset and then the wiper would continue, and then stop again, etc...So I just changed the motor. But to my surprise, that problem has continued. Also, the intermittent wipe stopped working. When the wipers are selected to any intermittent setting, they will move half way up the windshield, stop, and then begin operating continuously, with no delay. I replaced the wiper delay control module while under the dash today, but that did not correct the #$^%@ problem! SO I have reinstalled the old module for now. Is this a problem with the motor? Did I just get a crappy rebuilt one, or is it perhaps something else???
As I began to wrap up the projects for today, I corrected a minor nuisance with the instrument panel display. I have always found the high-beam indicator to be quite annoying on these cars. For those who are not familiar, it is placed at the top of the instrument panel, just below the dash, in the center of the turn signal indicators. This location puts the high-beam indicator quite high up into your line of sight. When driving on a dark road at night, when high beams are most needed, there is that big old stupid blue symbol glaring in your face! I wanted to dim this display for night driving, without risking making it too dim to be seen if i should turn the headlights on during the day, for example when driving in the rain. And so, I have changed the original bulb to a dimmer bulb. The original Chrysler spec was a #158, which has been replaced by #194, both 2-candlepower bulbs. I replaced mine with a #151, which is 1-candlepower. I think this will do the trick, but if it is too dim, I will try to find a #124, which is 1 1/2-candlepower. Am I the only one who has found that light annoying?? If anyone else feels the same, I'll report how these bulbs workout when I get it all put back together.
Reply from Dick:
I never read through this whole post until just now, and I see something I can maybe help with. I think the bright light indicator will still be much too bright, even with the 1 CP bulb in it. I suggest you try to find a 24 volt bulb with the same socket arrangement, that will reduce the light by about a factor of ten, which is what you are going to need for comfort at night. I certainly agree it is a pain in the butt, since it will not dim with the other dash lights, and since I often drive on very dark high desert roads, it drives me nuts! I drape my handkerchief over the top edge of the dash to keep it from blinding me. Blue is the most intense color for me anyway (I'm color blind, and blue lights just ZAP me!).
If you can't find a 24 volt bulb to fit at your local aircraft supply store, then we could work out a dropping resistor to reduce the voltage at the bulb to 6 volts or so, which would have the same effect.
Your wiper delay module and motor problems sound quite mysterious. I wonder if there is some poor ground connection, either on the delay module or at the motor. I have occasionally noticed a reluctance to park, but turning them back on again and then off always makes it work right, I assume this was caused by a poor connection within the motor on the park contact.
Question from Greg:
That flashing parking light bulb is # 257 same as a # 57 but has an internal flasher. You might try NAPA for them. While I on the subject does any one know what a # 53X lamp is? The 66 Imperial service manual calls for the 53X in some of the dash lights. A # 53 lamp works just fine but I would like to know what makes it different from a plain old # 53. Any one know?
Reply from Dick:
A 53x has a specified brightness (1CP), while the standard 53 does not. The 53X has a closely controlled filament location, the standard 53 make no mention of this. Also, the 53X has an "indefinite" life rating, while the standard 53 has a rating of 1000 hours. Probably the 53X is built to a higher quality control standard, and has a more robust internal supporting structure (that's a guess, of course). All 53's have the same voltage and current rating, so there can't be much difference in light output. There are 53R's, 53G's, and the two above.
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