96 Regal GS Battery light comes on after driving

[gshep]

My last post on this subject was after work in the shop, which included installing a reman PCM for stalling, upper intake plenum for cracks and a new tensioner pulley because the old one was GONE, my battery light was coming on after 1-2 miles driving. Also the mechanic did leave the hood up over night with the light on and had to recharge the battery. Because my load tester showed the battery as good, but just barely, and because the light came on after alomost the same amount of driving time every time, I was convinced the reman PCM we installed was faulty. Alas, no. I tested the battery on my load tester which showed the battery marginal and Autozone's which condemed the battery. I installed a new battery and still have the EXACT same fault. Battery light turns on after 1-2 miles driving. Does anyone have any thoughts other than the alternator? Could the mechanic have caused something?

[BNaylor]

Since the PCM monitors the alternator output and generates the light then I would suspect the alternator. It is detecting either an under or over voltage condition. It was 50/50 between the battery and alternator and you already illiminated the battery as a possibility. Other possibility is the wiring at the alternator. Good luck!

[gshep]

Thanks Bnaylor. I appreciate also the previous info from you. Having worked in the auto service industry for some years, I know coincindences happen to others, but surely not to me. LOL! The saving grace is that the battery was at least 4 years old so it did not hurt putting a new one in. On to the alternator I guess.

[gshep]

ARGGHHHHHH !!!! OK, after installing a new battery, the light came back on so I bought a alternator today. Salvage but bench tested at a local starter/alt shop and output was great. Around 14.2. Installed the alternator, test drove the car and like clockwork, the battery light comes back on. Went to the local Autozone and their tester showed no alternator output. Now I only half trust the counter guys but I saw no output. Sooooo.....Can anyone tell me where the fusible link is? The wiring diagram shows the red wire from the 4-pin alternator connector going to the starter I think. Can I just run a straight wire and bypass the existing one? Remember, this has 188,000 miles and is mainly used by my daughter back and forth to school and work. Usually no more than 5-6 mile per day.