'89 dash light and guages

My '89 s-10 Blazer's dashboard has gone whacko. The dash lights wil go out and the guages run to half-scale. Then, just as suddenly, it goes back to normal. This happens at night usually, and seems to be tied to the headlights being on (Duh, when the dash lights are lit), but the guages also go whack. The radio cuts out along with its lights at the sam time.

It started happening after I had to tear up the dash to get the heater core replaced. I had to lift the whole dash up to get in there. I feel that I disconnected the ground wire for the dash, somewhere under there.The circuit dia. in my Haynes manual shows the "ground" return as common to all these things that feed from seperate fuses.

By the way, the power plug (cig. lighter) has a good ground and the glove box light works fine. Go figure, don't need either one.

Just to confuse the issue, I measured 14 volts at the cig lighter; 11 volts, with the truck running; and 6 volts with the headlights turned on... AND I can get the dash lights on bright, with the guages normal, by turning on the dome light and opening the door! INSANE!


Any ideas?

Anyone know where the the "ground" wire attaches?

What's that lump of 'tronics behind the glove box? Does that have a ground in it?

HELP ME, Mr. wizard!

/satisfied, Frd?
//had to get away from that vibrator post

And this only happens when the headlight are on right?

And this only happens when the headlight are on right?

The lights are only with headlights on, of course, but the guages stay accuracy-challenged with or without the headlights. And the radio goes out, too.

Today, I took out the door switch and shorted the white wire to ground and turned the dimmer to the dome light position. That gets me around the problem, but it'll bite me again...I know. I'm still huntin' this, but I need to go inland tomorrow early.

Again, my Haynes manual circuit diagram only shows one wire to the door switch, and it's white/black. I actually have two; a white and a tan. the manual also doesn't show how the circuit from the dimmer knob to the indicator goes. It just says variable voltage off a 5a fuse at the fuse block.

I'm dissappointed in the manual.

I think your problem might involve the headlight switch.