I have an 86 T/A and everytime I turn the parking or headlights on, the headlights keep dimming in an out and so do the interior lights under the gauges. Whats wrong? How do I go about fixing this problem? Is it just a bad ground or something?

 

I am having pretty much the same problem


when I use my headlights, my dash, headlights and interior light with light on or door open will kinda of gently strobe, or dim and brighten as the engine idles.

It seems I am getting proper voltage.


Heeeeeeeeelp

 

If the dimming is erratic/ irregular then it could be fusible link A or its connection to the starter, or the C100 firewall contact.
If the dimming has a regular frequency to it and only at idle then it's just the regulator in the generator being slightly unstable. Nothing to worry about, but if anything external causes it then it has to be a bad alternator ground or some bad connection to the sense/ input wires.
Here are power distribution and charging system diagrams for '84 T/A's.