TR5

I searched for this in the forum but didn't find anything exactly like it.

Ok, so I pulled my stereo out to search for a way to mount it better because somebody messed it up when they tried to steal it. I spent some time trying to shove it back into the recess when I was done and it seems I've messed something up. Now when I turn on my headlights all my interior power is gone: stereo, instrument panel, etc.

Here is a detail or two more:
I checked a few things with a voltmeter, focusing on the stereo. When the headlights are off I am getting all the correct voltages referenced both to the stereo ground and the car's ground.
When the headlights are on the voltage to the stereo that is meant to be switched on with the accessories is 0, and the constant voltage line is still 12 volts.
I checked the stereo ground with the car's ground to see if it was jumping, but it was not. It was always 0 volts, which is to be expected since all the interior power appears to be gone.


My working hypothesis, from reading other similar problems people have had, is that I allowed something to short in my "lights on" interior circuit. I assume that means the fuze would have blown but I haven't checked that yet, nor would I know which one to check. If this sounds reasonable, can you tell me what may have shorted?

If it doesn't, what else might it be?

The91XJ

There isn't any other wires running where the stereo wires are. I doubt you got into any of the headlight wiring. Check for a dimmer wire, it should be orange. When the headlights are turned on it dims the stereo display. I'm wondering if maybe that wire is grounding or shorting out.

Besides this wire, nothing else should be connected to your lights.

Fasthawk99

Mine did this and it was from the PO installing the radio by cutting the factory harness off and hardwiring what he though went where. the dimmer, illumination, and power wires were mixed up. I dont remember the exact match up but it took some sorting to get it back straight. I would pull your radio, and take your time seeing what exactly is what. There is a chart on here of what wire color is actually what in your factory harness.

77olds

The worst thing anyone could do is cut into a factory wiring harness when there is an alternative - a wiring harness adapter.

Anyway, sounds like you've got your dimmer/illumination wires crossed with something else.

If I'm not mistaken, the wire for the dimmer (when you turn your head lights on, the radio display will dim) is orange in color. Seems to me that maybe you've got that crossed so that when you turn your lights on, it's shorting out and power is not getting to the instrument panel or radio.

freegdr

check for loose fuse in fuse box radio, radio clock illumination and dome lights are all on the same one

TR5

Thanks for the replies.
I checked the wires behind the stereo and i found that where the switched power wire was supposed to go they had put the illumination wire. So cool, I can swap that out with the switched power to get my radio to work as long as my car is on, but my instrument panel still doesn't come on.

The dimmer wire (orange) and the switched power were both taped off by me just after the problem began, so they can't be shorting right now. Also, the fuses are not blown. However the problem has not gone away.

My illumination wire has +12 volts when the headlights are off and 0 when the headlights are on. Is this how it's supposed to be?

Something else must have changed because even with the illumination wire connected to my stereo it was still working fine with the lights on or off before this. I have a feeling that changed for reason that's somehow connected to my instrument panel lights going out..
but I really don't know how.

poorstang

Is the illumination wire hooked to anything? If it is unhook it and tape it off. And ur problem should be gone

TR5

Since removing the illumination wire from the radio and connecting the proper power wire, the illumination wire has been taped off.

Does anyone know where I could find a wiring diagram for the instrument panel area?