Dash Instrument Lights Out

[ghjedi]

Hello,

I'm having some electrical issues with my 72 Challenger that I'd appreciate some help with.  My dash instrument lights are all out and yes, I've tried adjusting the dimmer switch     I normally drive the car during day light, so I can't tell when this problem started, but these lights were working fine for roughly 12 months up until recently.

I found out the hard way driving home late one night that my tail lights were out, but I fixed that fairly quickly by replacing the fuse that had blown for some unknown reason.  I was hoping that fixing my tail light issue would fix my instrument cluster lights, thinking that the instrument lights were out to tell the driver that there was an exterior light issue.

All of my electrical switches seem to be working now, except for the instrument cluster lights and the wiper motor.  It seems hard to believe that all 3 instrument bulbs and my wiper motor burned out at the same time, so I'm wondering if this sounds like a fuse issue or not.

When I was replacing the tail light fuse, I thought I checked all of other fuses and they looked good.  Then again, I was only focused on the tail light issue.

Does this sound like another fuse is blown or something else?

[mopar12372]

the first thing you do searching for electrical gremlins is check the fuses,  blown replace continue searching .(there is a reason for the blown fuse)

remove any out side electronics that is ADDED to the car and MAKE SURE  it has its own circuit .(example amp hooked up to wiper circuit )

second check the items in that circuit for loose conections . wires rubbing on body or another circuit.

third  i would find every ground terminal in the car sand and clean to make sure the conection is good

fourth i noticed that the wireing on mopars has a bulk head that is pushed together (fuse box) 9inside and out )alot of problems can be eleminated by seperateing them cleaning up and makeing sure every terminal is makeing contact.

good luck !!!

[Jamiez]

The dimmer switch is also a common point of failure.  They tend to corrode and cease functioning.  Someone with more knowledge (like Slotts) can probably tell you how to bypass the switch or how best to test it.

[ghjedi]

Thanks guys for the input.  I will definitely check the fuse tomorrow, but like other issues I've encountered, I highly doubt it will be resolved by a simple fuse replacement.  I agree with you that fuses blow for a reason, so that's what I'm worried about.

At any rate, I'll update this post, once I check the fuses again tomorrow.

[ghjedi]

I just checked all of the fuses again and they look fine.  I specifically checked the "INSTR" fuse, thinking this is it and it looks fine.

I guess my next thought is to pull off the instrument cluster and check the light bulbs, but is there anything else I should try first?

[Chryco Psycho]

it is easy to drop the light bar & check for power but I doubt you have power there , next I would pull the switch panel & see if you have power in & out of the dimmer switch

[MEK-Dangerfield]

Don't judge a fuse by looks. I've got a great looking 30 AMP fuse that came with my aftermarket amp, that is dead as a doornail.   

Do you have volt meter to check both sides of the fuses with the ignition key turned to "on"?

I still have to lean to a bad dimmer switch.   

[ghjedi]

Don't judge a fuse by looks. I've got a great looking 30 AMP fuse that came with my aftermarket amp, that is dead as a doornail.   

Do you have volt meter to check both sides of the fuses with the ignition key turned to "on"?

I still have to lean to a bad dimmer switch.   

Thanks and that is a great point.  I do have a volt tester somewhere in my garage and I'll give that a try.

[bandt]

Like MEK said check for continuity on all your fuses.
I was blowing a fuse everytime I'd put my lights on. The gauge lights, marker lights, run through the MISC fuse. I had a short in one of my rear marker light wires.
 If your fuses are good check to see if you are getting power from your headlight switch and from your dimmer.

Brian

[ghjedi]

Like MEK said check for continuity on all your fuses.
I was blowing a fuse everytime I'd put my lights on. The gauge lights, marker lights, run through the MISC fuse. I had a short in one of my rear marker light wires.
 If your fuses are good check to see if you are getting power from your headlight switch and from your dimmer.

Brian

Thanks for the suggestion.

I probably won't get a chance to play with this again until Friday afternoon, but I like yours and MEK's ideas about testing the fuses vs. the visual inspection I did. 

By the way, I incorrectly stated in my initial post that my wiper motor was not turning out.  To clarify, the wiper motor is working, as are all other interior and exterior lights.  The only exception is my front driver side marker light, which is another one I'll have to look into this Friday.  The other front and both rear side marker lights work fine.

[ghjedi]

Here's a brief update on my saga:

I used a circuit tester and confirmed the fuse is working and there is power there with the key on.  I then replaced all of the 4 light bulbs, but still no luck.

I'm thinking the next step is to test the switch, as that seems to be likely failure point.

Any other suggestions?

[Chryco Psycho]

the power will go to the switch next so that is where I would check , I believe it goes through the headlight switch first & out to the dimmer

[mopar12372]

try to wiggle the dimmer with faness to see if the lights turn on.

[ghjedi]

the power will go to the switch next so that is where I would check , I believe it goes through the headlight switch first & out to the dimmer

Thanks-- I'll check that next.  The good news is that my headlights and parking lights work fine.

[Jamiez]

The light bar grounds to the body through the mounting screws.  It's possible they could be corroded and not grounding.  If your meter can be set to read ohms, you can connect it to the light bar casing and then a good ground.  It should read 0 (or very close to it).  If it reads a very high number (or overload or similar) then you have a grounding issue.