: no dash lights

09-09-10, 10:32 AM
i was installing a new radio in my 88 and after i got it hooked up and started the car the instrument panel was dark(fuel gauge, spedometer, etc. everything but the a/c) and when i turn on the headlights the lights on the a/c went out. the radio lights up and was working fine but i took it out and the problem is still the same. i have installed other radios in this car and never had this kind of problem before. i have checked most of the fuses..if it is a fuse i dont know which one im looking for because the ones that i thought might be the problem are all intact(radio, tail light, a/c, and all the others i could reach on the fuse box by the brake). i'm stumped but i still think(hope) this is an easy fix..any ideas or suggestions would be greatly appreciated.

09-09-10, 11:16 AM
Did you try turning the dimmer control knob on your headlights? You can turn all the instrument lights off and the climate control display using that...I have duplicated that problem with that knob, worth a try...

09-09-10, 12:51 PM
Many GM vehicles have two fuses that control the stereo. One gives basic power to the stereo to work the display and backlighting. The other actually powers the radio and speakers. If you hooked up the radio power to the wrong one, you'll have lots of issues. I'm willing to bet you hooked the radio's switched power to the always on wire and the always on wire to the switched wire. By switched power I mean it's only hot when the ignition is on. Double and triple-check that harness you made and then work your way back to the fusebox and then the headlight switch with a multimeter. If there's a short or groundout somewhere, you'll find it.

09-09-10, 05:14 PM
thanks for the suggestions. i had already checked the dimmer knob but i can try again when i take another look at those fuses.

09-09-10, 06:05 PM
On a 1977, the dash lamp fuse is (I think) upper left near the signal relay. Might be the same for a 1988....maybe. IIRC it is a 10 amp fuse.

To make diagnosis easier, I have replaced all my fuses with the Bussman fuses that have LEDs that light when they fail. I think I paid $12 for a kit of them at AutoZone.

09-10-10, 12:22 AM
Same thing happened to my car when I shorted the hood lamp. Check and replace the LTR fuse. It's a screwed up circuit, but the under hood lamp, dash lights, radio, audio alarm, and cigar lighter all have connections to the LTR (even though most of them have their own fuse).

09-13-10, 10:55 AM
Finally found the problem. It was a 5 amp fuse labeled I/P near the top of the fuse box. I think I missed it the first time because its difficult to get to. Im really relieved because I was just about to take it to the shop. I had called a mechanic shop and they told me it was the computer (BMC I think) which would be a couple hundred to have replaced. Thanks again everyone for all the good ideas.

09-13-10, 04:23 PM
Do not believe anyone who tells you the computer is causing anything that isn't engine related on an 11th gen Cadillac Brougham. You could swap the computer for a box of matches and never know the difference (if the proper changes were made to the engine).

But yours isn't rear wheel drive, is it?

09-18-10, 02:32 PM
it is rear wheel drive

09-18-10, 11:50 PM
^For what it's worth... "Fleetwood d'Elegance" was the '85-'88 designation for the front wheel drive Fleetwood, which was an option package for the '85-'92 Sedan de Ville.

You have a Brougham d'Elegance.

09-20-10, 01:08 AM
Yeah, I learned this myself once when a lighter socket was overloaded he dash light and radio all died together. The circuit for these is designed in an asinine way.