1987 Park Ave 3.8V6 Automatic 162K. The lights on my Buick flicker, (headlights, interior lights, etc) This usually occurs at idle like when I'm at stops signs and lights. It doesn't seem to be a major problem but its annoying. All wiring has checked out to be fine and the AC Delco battery is less than a year old. I believe it may be the alternator as it occasionally makes a slight grinding noise. Any ideas?

I would definately be looking into a charging problem. An occasional grinding?

I'd second the alternator. Sounds like its not charging enough to keep up with the demands of the electrical system. ...and if its grinding internally then I'd say its a goner anyway.

Remove the alternator and have it tested for free at pretty much any parts store (Autozone, O'Reily, etc). Removal should be 2 13mm bolts, an electrical connector, and I think an 8mm bolt to the negative battery cable.

OK, I noticed some melting around the wiring connector that plugs into the alternator. I cut if off and replaced it. It works alot better but I still notice an occasional flicker. I really can't tell if the grinding noise is coming from the alternator or the power steering pump, which is right behind the alternator. I think the connector is what I needed atleast for now. I have a POS Grand Am with a good matching alternator and PS pump if I need to swap. Thanks...

Any griinding that is "occasional" usually suspects the water pump

It's at the top. Definately alternator. I think the tensioner was jerking it. I caught it jumping and lube it up. It's not as bad and no more loud grinding but I will watch the alt. It still has a faint grinding to it but not as bad.