Alternator not charging the battery (Different issue) - Third Generation F-Body Message Boards

Electronics Need help wiring something up? Thinking of adding an electrical component to your car? Need help troubleshooting that wiring glitch?

Alternator not charging the battery (Different issue)

Thread Tools Search this Thread
Old 04-27-2009, 09:15 PM   #1
Junior Member
Thread Starter
Join Date: Apr 2009
Location: Coolidge, AZ
Posts: 72

Alternator not charging the battery (Different issue)

Someone please help me out. Here's the deal. My alternator has not been charging my battery and I couldn't figure out why, so I started tracing cables. Here's what I found.

It APPEARS the positive battery cable is grounded to the car (intentionally or unintentionally). The positive battery cable has TWO cables. The first, of course, is the big thick red cable. The second, is a black cable with a red stripe. It appears to be grounded to the car. ALSO, there is another smaller black cable with a red stripe that is terminated and it runs back toward the car. Not sure what it is. Where it is grounded, it appears that there are other cables that are for power, but what they're supplying, I have no idea, but two of the cables (orange and red) appear to go to a plug on the passenger fender.

Overall picture of the battery tray:
Name:  DSCF4541.jpg
Views: 22
Size:  569.6 KB

Picture of mysterious small black cable with red stripe:
Name:  DSCF4543.jpg
Views: 22
Size:  483.2 KB

Picture of black and red battery cable apparently grounded to the car. Notice the other cables that I think the intent was to provide power to...though I'm not sure:
Name:  DSCF4545.jpg
Views: 34
Size:  608.9 KB

Mysterious plug that an orange and red wire run to:
Name:  DSCF4546.jpg
Views: 14
Size:  390.5 KB
Devryn is offline   Reply With Quote
Old 04-28-2009, 11:45 AM   #2
Join Date: Mar 2005
Location: Tyndall AFB, FL
Posts: 132
Car: 1985 Z28
Engine: 305 TPI
Transmission: 700R4
Axle/Gears: garbage 2.73

Re: Alternator not charging the battery (Different issue)

Your negative terminal is the only thing that should be grounded. Run the big one to the motor, and a smaller one anywhere where you can find a good ground. The positive terminal should have the large cable running to the starter, along with a smaller one that has some fusible links (3 i think?) on it. Kinda getting ahead of myself so let me slow down.....

First of all....whats the volatge/amperage coming out of the alternator? Remember, for the battery to charge, the alternator has to put out more voltage than the battery has. This is called a positive differential. Your alt should bang out 14-15vdc @ around 40-60amps at idle. Check this first, it will tell you if your alternator is even serviceable or not.

Second.....make sure your charging line from the alternator to the battery is actually connected properly. You can trace the wire from the back of the alternator by hand which would be the most accurate, or if you have access to a multimeter, set one lead on the alternator charging post and tap the other lead on each POSITIVE battery wire until you get continuity. If you never get continuity, then either your charging line is broken or not corrected properly.

As for the pictures....I hate the firewall we have here, so I'll take a look at them when I get to the house and see if I can come up with any more explanations.
kcallais is offline   Reply With Quote
Old 04-28-2009, 12:03 PM   #3
Junior Member
Thread Starter
Join Date: Apr 2009
Location: Coolidge, AZ
Posts: 72

Re: Alternator not charging the battery (Different issue)

Tyndall? I was at Sheppard for 4 years (2002-2006). Edit: I was thinking Tinker...oops. It's be awhile. I was AF for 6 years.

I had someone who knows more than I do look at it yesterday, and the "thing" I thought the cable was grounded to was actually plastic, and seems to feed power to a few other wires and isn't actually grounded. I can e-mail ya the pics if you'd like.

Last edited by Devryn; 04-28-2009 at 02:00 PM.
Devryn is offline   Reply With Quote

Related Topics
Thread Thread Starter Forum Replies Last Post
Chronicles of a 9 Second Trans Am... Final Chapter Street Lethal Power Adders 383 09-17-2017 02:03 PM
New Owner - Chicago IL Skwisgaar Mid-West Region 14 09-01-2015 09:41 AM
89 IROC Issues (Starting & Running)-Logs Included Cornholio7979 TPI 3 08-30-2015 05:17 PM
[MD] 1990 Trans Am drag/bracket car with trailer Dialed_In Firebirds for Sale 2 08-20-2015 02:45 PM
Alternator Fusible Link/Circuit Breaker triggers when A/C is turned on db057 TBI 10 08-11-2015 11:11 PM

Go Back   Third Generation F-Body Message Boards >

1988, alternator, batery, battery, cable, cables, car, charging, firebird, good, grounded, pontiac, positive, properly, red

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Featured Sponsors
Vendor Directory

1982 Camaro '82 || 1983 Camaro '83 || 1984 Camaro '84 || 1985 Camaro '85 || 1986 Camaro '86 || 1987 Camaro '87 || 1988 Camaro '88 || 1989 Camaro '89 || 1990 Camaro '90 || 1991 Camaro '91 || 1992 Camaro '92

All times are GMT -5. The time now is 06:59 PM.

All content copyright 1997 - 2014 All rights reserved. No part of this website may be reproduced without the expressed, documented, and written consent of's Administrators. We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to and affiliated sites.
  • Ask a Question
    Get answers from community experts
Question Title:
Your question will be posted in: