No instrument illumination

[Tarscien]

After taking my dash out to clean it, I now have no illumination for the instrument panel or climate control. I've checked all the fuses to make sure that non are blown, and I've gone so far as taking the whole thing back out again to make sure all the connections were made. They were. There is a single plug, covered with foam, located under the drivers side dash which I can't find a mate for.
Some info about my car:
91 talon N/T
AC
P/M

That's about it. The stereo still works as do all the signals and the instruments themselves, just no illumination. I don't want to have to use a flashlight to drive at night. Any suggestions would be very appreciated.
Thanks alot

 

[laserblue]

Last year I pulled my dash apart.... and from shaking it around, every single bulb filament broke; they grow fragile from old age.
Now, that's probably NOT what's happened to you, but I thought that I'd tell my story!
Make sure that the dash plugs are fully seated. It's difficult to see, since they plug in when you shove the dash unit into place. Also triple check that the plug that goes to the dimmer control switch/knob/thingy is inserted tightly.
All the "dim-able" stuff in the dash get's its power from that dimmer circuit.
..... BTW- is your radio 'factory' or 'aftermarket'? If it's 'factory', then the radio buttons also "dim" from that same circuit. Do they work?

 

[Tarscien]

I didn't know that they all get power through the dimmer swith, I'll have to check that. I know that the filaments aren't broken because I switched all of the bulbs to LED's. I guess I forgot to mention that. The radio is aftermarket but I hooked up the dimmer to it as well. It wasn't working either so it makes sense that it might be my dimmer.

 

[Tarscien]

I just tested it and I have no voltage running to my dimmer switch... Where would the problem be?

 

[laserblue]

I'm not sure what route the voltage takes. I don't have the wiring diagram.
The voltage may come into the switch first, and then go thru the bulbs to ground -OR- the 12v may first connect to the bulbs AND THEN go thru the dimmer switch to ground, so it's difficult to diagnose over the internet!!

Please!!!!!!!! ANYONE--- Do you have a schematic?

It would make sense that the circuit would tie into the parking lights switch somehow, since the dash lights up when the parking lights are on... but ........ who knows?

I wish that I knew more. Do you want me to go to my dealer and look thru the service manual? The place is only a mile away.

>>> Did you take the voltage measurement with the plug connected to the dimmer switch, or unplugged?

 

[1LE]

Check your taillight fuse. You may have shorted a wire. Another symptom of that is that your parking lights would not come on.

 

[luv2rallye]

In my '99 manual it shows the power goes thru the tail light relay, then the fuse, then instrument panel lights, then dimmer, then to ground. Maybe that will help.

 

[Tarscien]

I must have blown a fuse while checking the thing cause I just checked the fuse box again and pulled out my 2nd blown tail fuse. Now I have power running to the dimmer so I'm assuming that the dimmer is what is blown. Does anyone know what the proper readings are for a working dimmer switch? There are 4 pins in this one but only 3 of them are used.

 

[luv2rallye]

I think your dimmer switch (rheostat) is blown. One of the wires goes to the fuse (power) and one to ground and one to instrument lights. If the fuse wire is shorted inside the switch to the ground wire....poof goes the fuse. Disconnect the switch. You should not have 0 ohms resistance between pins 4 and 3 of the switch.

 

[Tarscien]

Problem solved. This was real tricky. I took reading on my dimmer and yes, it turns out that it was blown. But every time I hooked the whole thing up, that tail fuse would blow. It turns out that on a completely separate wire, going into a different button, 2 of the wires were stripped just enough and were touching, ground to power. I separated them and taped them up, plugged everything together and bingo. it all lights up now. But no dimming. I guess that when the dimmer is blown, it gets stuck on full open. Thanks for all the help and suggestions. Now to find a new dimmer.