I was driving around today, and I noticed that all the idiot lights turned on. But all the idiot lights were really dim, I could barely see them, and if I gassed it even a little bit, all the lights would go away. But if I cruise in neutral or am stopped, the lights would come back on.

I've got an 89 N/A, battery is 1 year old, alternator is an FD alternator I got off silverrotor about 6 months ago, and the belt is new cause I needed a longer belt for the FD alternator. So most of the stuff is new, I don't see it malfunctioning.

At first I thought maybe the belt was slipping, but if that was the case, the idiot lights should come on when my engine is working harder. Am I right about this?

My guess is that it's my grounding. I've noticed that my dash voltmeter significantly drops when I have a lot of electricals on (ie. heater, wipers, lights, etc). I've been meaning to replace the grounds, or at least add new ones in, but i haven't had the time to.

So my question is, could poor grounding be the cause of the idiot lights going on, or is this most likely an alternator malfunction?

 

You can get the alt and battery tested at a shop. I would go that route.