While driving at night the dash lights, including radio and ac/heater controls will flicker on and off. I've read through several posts and some say it might be a bad battery while others say it might be a bad ground in the wiring harness. I'm going to try the battery first, but just in case that doesn't work does anyone know where the the wiring harness grounds to the chassis? I'm really unsure where to start looking. Any help is appreciated.

 

My 84' had (has?) kind of the same problem. However, the only thing that would completely cut off would be the headunit to the radio. First started doing it when I put my KC lights on. When I would turn them on, if I was at an idle did anything to draw more current from the alternator (even just pushing the brake pedal so the lights lit), the headunit would cut off then back on.
I put a new 140AMP Powermaster alternator on, and problem only got worse.

One thing it turned out to be was the belt coming loose because I did not tighten the alternator nearly enough to keep it stationary, so it would loosen up a bit over time.
I also took the headunit's ground wire and sanded down all the surface rust on the loop of the wire and the ground.
I still have to clean the battery terminals off real good, but I can't get the positive to loosen until I get a terminal puller.
It does it every now and then after doing that stuff. I'm sure once I clean the terminals up and possibly get a slightly smaller alt. belt due to the new alternator's pulley being a little smaller, I won't have to deal with the problem again anytime soon.

I'd say make sure your alternator is good, make sure the belt is tight, check connections and grounds. Could check the battery as well.