73T: Alternator warning light glows at low RPM: Problem?

[Andy Ring]

I've noticed that my alternator warning light glows dimly (not full strength) when my car is at an idle. As soon as the RPM comes up the warning light goes out. So far, I have not experienced any battery problems or other signs of a bad alternator. My belt does not appear to be slipping. I have not had a chance to test the voltage across the battery yet at idle, but was wondering whether my alternator is about to go bad. Any advice (or tests I could perform) would be appreciated.

Thanks in advance

[billwagnon]

what RPM? If mine gets below 800-1000 the light comes on

[Andy Ring]

Yeah, its probably only when it goes below 1000. However, I don't remember it coming on previously at below 1000. Actually, I'm happy that yours comes on too because I was hoping that it was "normal" behavior.

[Early_S_Man]

Andy,

Classic case of the 'Zero-Ampere speed' of the alternator increasing over the years due to additional resistance build-up from corrosion at the #61 terminmal of the alternator, or either of the 14-pin connectors, or at the lamp holder for the warning lamp!

Here are some threads discussing the matter:

http://forums.pelicanparts.com/search.php?action=showresults&searchid=787810&sortby=lastpost&sortorder=descending

[Andy Ring]

Warren,

Thank you for both the info and reminding me to check the archives before asking a question. My mistake--thanks for not making me feel too stupid.