Alternator charging but Battery light is on

[MacinTek]

The voltmeter shows the alternator is charging, the battery has plenty of juice to start the car quickly but the battery idiot light remains lit while driving. Anyone seen this behavior in a major appliance? (Dr. Peter Beckman, Ghost Buster et al).

[Michael]

First check to see if the belt is still there, then see if it's loose.

If the belt is tight, you want to check the plugs at the alternator to see if one has come loose, then check voltage at the battery. If all of that is ok then you need to test the battery and alternator.

[Bitsyncmaster]

I have seen it with an overcharging alternator. What alternator do you have and what voltage readings are you seeing? Have you checked the voltage with a meter on the battery?

[Ron]

What type of alternator (Motorolla, Duceller, Delco type,...)?
Is the brilliance while driving roughly the same as when the key is on but engine not running?
Battery voltage at idle and at 1200+ RPM using volt meter?

EDIT: No reply, then 3 at once LOL

[MacinTek]

What type of alternator (Motorolla, Duceller, Delco type,...)?
Is the brilliance while driving roughly the same as when the key is on but engine not running?
Battery voltage at idle and at 1200+ RPM using volt meter?

EDIT: No reply, then 3 at once LOL

Gawd only knows what's in there. It's an '83 so it probably shipped with a Motorola but, I think it got replaced a while back. My father kept terrible records of things as mundane as his car. I'll probably replace it soon since I'm sure it suffered some ill effects when the starter kept shorting out.

Symptoms when it shorted out while I was driving were... tachometer goes nuts, I smelled smoke... stopped car and it wouldn't start... and I was at the smog test station when this went down. 11 months later, I can get it smog'd just in time to pay next year's registration.
:repost:

http://dmctalk.org/attachment.php?attachmentid=36992&stc=1http://dmctalk.org/attachment.php?attachmentid=36993&stc=1

[Ron]

There should be a small brown-yellow wire going to the alternator. It comes from the light. Could of came off and/or grounded to the exhaust or ??
Find it and, with it disconnected, turn the key to on, use a jumper wire to ground and un-ground the wire - The light should go on and off. This tests everything involved but the alternator itself. If OK, run by Autozone and they can check the alternator on the car...

[Bitsyncmaster]

Those brown wires are probably breaking off the terminal or pulling out of it. That sharp bend in the wires is not a good idea.

[Jonathan]

Anyone seen this behavior in a major appliance? (Dr. Peter Beckman, Ghost Buster et al).

Haha, nice! You're gonna fit in here just fine!


Those brown wires are probably breaking off the terminal or pulling out of it. That sharp bend in the wires is not a good idea.

Don't cross those wires... it would be bad! ;)

[David T]

Haha, nice! You're gonna fit in here just fine!



Don't cross those wires... it would be bad! ;)

Remove the alternator, get it tested, then repaired or replaced. Also have the battery tested.

[DMC5180]

I had to fix the photos😜

http://images.tapatalk-cdn.com/15/09/27/d3143dabb4f369f16f41905abcdd368c.jpg

http://images.tapatalk-cdn.com/15/09/27/41847521f672d1ec4bf4c3a83175d8e5.jpg




Dennis

[Ron]

I had to fix the photos

Hehe!
(I still don't see the N/Y wire ;-)

==========

Confirm the lamp circuit isn't shorted before pulling the alternator...

[DMC5180]

The N/Y wire is covered by a thick black sheath. His is somewhat hidden by the 3 brown wires. Judging from the direction it running to the small terminal stud on the LH side. My (removed Motorola) had the N/Y wire connected to the terminal stud on the RH side near the Large wire connection.

According to some images I found, both of those terminal studs are labeled as Stator. Whether one is meant to be used over the other I'm not sure.

http://images.tapatalk-cdn.com/15/09/27/773c4019f4edc9f071fd75a3b0b4be05.jpg


Dennis

[PJ Grady Inc.]

Gawd only knows what's in there. It's an '83 so it probably shipped with a Motorola but, I think it got replaced a while back. My father kept terrible records of things as mundane as his car. I'll probably replace it soon since I'm sure it suffered some ill effects when the starter kept shorting out.

Symptoms when it shorted out while I was driving were... tachometer goes nuts, I smelled smoke... stopped car and it wouldn't start... and I was at the smog test station when this went down. 11 months later, I can get it smog'd just in time to pay next year's registration.
:repost:

http://dmctalk.org/attachment.php?attachmentid=36992&stc=1http://dmctalk.org/attachment.php?attachmentid=36993&stc=1

FWIW this appears to be an original alternator because all 83's delivered through the Sommerville N.J. prep center were undercoated and have a similiar finish to what is sprayed on this alternator. I noticed back then that the alternator usually recieved the undercoat treatment as well which is rather unusual practice in the industry. If the undercarriage has been undercoated (Body Schutz) you can be pretty sure the car was first delivered to an east coast owner and was undercoated at the N.J. prep center. It's probably time for a new one.
You should also check your fuse/relay box for heat damage as the smoke smell most likely originates from a problem there. Also check all grounds as tach fluctuations are usually ground related. Of particular importance is the battery cable ground to the TA bushing R/H rear mounting bolt.

Rob