Mechanics

99 TRANS AM BATTERY CHARGING ISSUE

1999 Pontiac Firebird

Electrical problem
1999 Pontiac Firebird V8 Two Wheel Drive Manual 66000 miles

Hello, I'm having a problem with my Battery charging on my 1999 Trans Am. The car will not charge the battery over 11.8 volts. I installed a new Optima Battery, Alternator, Battery Cables, and even a PCM (I was originally getting DTC P1638 Generator L-Terminal Wire). With the car running, I am measureing 14.4 volts at the battery but for some reason it will not charge above 11.8 volts. When I connect a home charger, it will charge to 12.66 volts. I've been trying to diagnose this problem for about a year now so any help would be greatly appreciated.

Thank you in advance!

Jason
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1999TransAm
September 30, 2008.




Hi Jason,

Thank you for the donation.

I don't understand your question fully.

When engine is running, voltage is 14.4 v at battery? When does it become 11.8 v?

Did you test charging voltage after running for 1/2 an hour?

KHLow2008
Oct 1, 2008.


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