Cruising down the highway, and the seatbelt light will turn on...then it goes off, seemingly haphazardly. If I remove my seatbelt or giggle it, the light does nothing. Any ideas what to check? Car is low miles and original. I'm not sure where to start.

 

Based on the electrical diagrams it looks like theres a sensor or switch on the receiver of the belt (the end by the console). I would check continuity, Maybe unplug it, clean it and plug it back in.

I found this in section H of the 1980 electrical diagrams manual on http://foxed.ca

 

Ok, I'll see if I can find the switch. I thought it might be a grounding issue somewhere else but it makes sense to start with the basics.

 

I know this isn't necessarily any help, but I have exactly the same issue. Randomly the seatbelt light will come on for 3-5 seconds, then go off again. I doubt its grounding at the panel, or else you'd have other issues, I figured it's just a faulty sensor.

Anyway, I just ignore it. If it ever comes on and stays on, I'll do something about it.

'85 GSL.

 

That's exactly what mine does. I think you're right about the sensor. Haven't seen it lately...but it sure does freak me out when I'm at an HPDE and lights on the dash start going off.