My 2000 Blazer 2dr 4x4 has some issues. When I start, not always, the battery light will be on until I get the truck up to speed for a minute. Had both the battery and the alternator checked. Both seem fine.

This morning it went to another level. The dash lights were on, but dim, and all the gauged were pinned at zero. Lights were dim. Battery light on. Then when I got on the road and got up to speed it just corrected itself.

I've had to replace the headlight switch a couple times, so I suspect it could be that, again. Somebody. Anyone?

 

Any belt squeal ? could be as simple as a bad belt or tensioner letting belt slip under heavy alternator load

 

No belt issues or noises. This isn't the only electric issue I have. Dim lights don't work. Thought it was the switch, but when I closed the hood one dim light came on. I was told to check my grounds.

 

I agree with the advice to check grounds maybe one is loose and intermittanly makes connections.