Alternator Starting to go out?

About four months ago, I was driving home from a camping trip and my lower dash lights started to slowly get bright, then they faded away. I figured it was probably the alternator, so I just tried to be mindful of if the lights came on again, but that didn't happen until about a week ago, while sitting at idle. I just happened to notice they were on, so I revved the engine and they went away and haven't come back since. Would a dying alternator last that long, or is it something else I should get checked? Would a bad alternator always test bad, or only when the lights would be showing?

Thanks,

[lee]

it could be connections, but mine did just as you describe, and finally gave it all up in about a month from where you are now.

What would be the cheapest route to fix the problem? Just go to AutoZone and buy one? I've read somewhere that it's easy to replace; just not sure where to start (I'll do a search).

[lee]

that's what I did (except I went to a local parts store with a good local rep - they got it from a rebuilder next day delivery). And yes, it's an easy switch, couple of wrenches and a half-hour (minus a wallet lightening experience of course).

I went by an autoparts store for a free alternator check. They tested the battery and alternator, and said both were fine (as best I could tell the Voltage displayed 13.7 or 13.9 something, I don't remember). If the alternator is fine, then what could be causing the lights to fade in and out? Do I need to clean the grounds (what are the grounds and where are they?) Thanks,

[lee]

there's a plug as well as the power lead that go into the alternator. Remove the battery wire first, then clean all contacts on the wires, as well as the alternator.

BTW, the voltage reading (I think) should be 14.2-14.8, but not sure if that's at say 2000rpm. was the 13.X reading taken at idle?

It was at idle.

[thumper_svx]

Try tightening the belt first. I had that about a week ago when it started to get cold... seems that the belt started slipping a little and there was more "give" in the belt than there should have been. A quick tighten with a ratchet and it's been fine ever since.

Give that a shot before you start pumping money into the alt.