So i have an 88 sport coupe and the gauge lights and gauges themselves go nuts when i turn on the headlights while the ignition is on. It doesnt do it when i turn the lights on with the ignition in the off position. It almost seems like a surge of some sort or something when i turn on the headlights. Im not really sure, but i am doing an LED swap right now and would like to correct the problem before i button her all back up! I know the electric board on the back is in good shape and making good connections. Does anyone have an idea? Thanks in advance!

Mine does the same thing, but only to half the dash. It's winter so I haven't had time to look into it. I asked a mechanic and he said it sounded like I had a bad ground. But, I can't confirm yet

check your grounds before you get it all put back in

Yeah, my right side (fuel, temp, volt and tach) are the only ones affected. It started several months ago even before i messed with it.

I had the same problem, Half of dash went dark with lights on, then it went to my gauges going haywire, the 3 wires to the back of my block had broken, i spliced them and reattached and everything has been fine sence