1998 Pontiac Grand Am

Tiny
EVO9393
  • MEMBER
  • 1998 PONTIAC GRAND AM
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 147,000 MILES
Start up ok 2 minutes later battery light comes on. Replaced altenator, battery and checked the grounds. Getting 11.80 on voltage from alt to battery. When running its 7.68. Replaced altenator again, same problem. Thank you, moe
Saturday, February 9th, 2008 AT 5:23 PM

4 Replies

Tiny
MASTERTECHTIM
  • MECHANIC
  • 4,749 POSTS
Moe you need to check the fat red wire at back of alternator for battery voltage, sounds like you might have no power there. Check back to us.
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Saturday, February 9th, 2008 AT 5:38 PM
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Those readings are just too low- for the engine management to operate properly-The field ciruit is computer generated-in other words the computer acts as a voltage regulator. See below


https://www.2carpros.com/forum/automotive_pictures/12900_alternator_4.jpg



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Saturday, February 9th, 2008 AT 5:44 PM
Tiny
EVO9393
  • MEMBER
  • 2 POSTS
Do I replace the computer? This is the closest ive been yet lol
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Sunday, February 10th, 2008 AT 9:44 PM
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
This is where I stop-If all checks out -the Alty, Battery, and all connections are cleaned and properly connected/tighten.

The computer is the last place I tell the customer to go-its not cheap-especially if there's a wire problem and you hook up the new computer and get fried in sec or 2. Your shot!

Go to an indepedent shop and have them take a shot at it with their machines_
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Monday, February 11th, 2008 AT 12:03 AM

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