New alternator not charging battery.
Thread Starter
4th Gear
Joined: Jul 2015
Posts: 4
Likes: 0
New alternator not charging battery.
I just replaced all of the power steering system in my '79. I took the alternator off to get the PS pump out and rebuild it. When I out everything back together, I had nothing reading on the dash voltmeter. I put my voltmeter on the battery and only had 12 volts. I metered the alternator with the same reading. New alternator put on, same thing.
I checked the fuse for continuity- good.
Took the GEN light bulb out and it tested good. It does not come on with the key on and engine not running or at all.
The battery is still not charging. So I jumped the brown wire to the small post on the alternator. Battery posts show 14+ volts.
I'm beyond frustrated and don't know what to check next! HELP!!!!
I checked the fuse for continuity- good.
Took the GEN light bulb out and it tested good. It does not come on with the key on and engine not running or at all.
The battery is still not charging. So I jumped the brown wire to the small post on the alternator. Battery posts show 14+ volts.
I'm beyond frustrated and don't know what to check next! HELP!!!!
2026 Loser of the Year
Joined: Sep 2013
Posts: 36,487
Likes: 6,967
From: New Or-leens Loo-z-anna
Rookie here.......it sounds like the alternator itself is good.....but it is not getting the proper connection through the "light bulb wire" to excite the alternator.
When you jumped the brown wire to the post it provided the voltage that the alternator needed.
Troubleshoot the light-bulb wire all the way to the alternator connector.
Sorry I couldn't be of more help.
When you jumped the brown wire to the post it provided the voltage that the alternator needed.
Troubleshoot the light-bulb wire all the way to the alternator connector.
Sorry I couldn't be of more help.
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
That small brown wire has been known to break internally- it looks good, but the conductor inside is broken. BE a place to start-
(Did the 79 have an electric choke? I know the later ones that did have the choke heater fuse would blow and no power to the brown wire)
(Did the 79 have an electric choke? I know the later ones that did have the choke heater fuse would blow and no power to the brown wire)
Melting Slicks
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
I just replaced all of the power steering system in my '79. I took the alternator off to get the PS pump out and rebuild it. When I out everything back together, I had nothing reading on the dash voltmeter. I put my voltmeter on the battery and only had 12 volts. I metered the alternator with the same reading. New alternator put on, same thing.
I checked the fuse for continuity- good.
Took the GEN light bulb out and it tested good. It does not come on with the key on and engine not running or at all.
The battery is still not charging. So I jumped the brown wire to the small post on the alternator. Battery posts show 14+ volts.
I'm beyond frustrated and don't know what to check next! HELP!!!!
I checked the fuse for continuity- good.
Took the GEN light bulb out and it tested good. It does not come on with the key on and engine not running or at all.
The battery is still not charging. So I jumped the brown wire to the small post on the alternator. Battery posts show 14+ volts.
I'm beyond frustrated and don't know what to check next! HELP!!!!
When you turn your ignition switch ON the rear bearing of the alternator will become highly magnetized (check it with a wrench or screwdriver). If it isn't then the small single-strand wire that plugs into the side of your alternator is likely broken and every auto parts store stocks those plugin wires with leads about 8" long for about $5.
Melting Slicks
Joined: Feb 2006
Posts: 3,105
Likes: 96
From: Sunrise FL
When you turn your ignition switch ON the rear bearing of the alternator will become highly magnetized (check it with a wrench or screwdriver). If it isn't then the small single-strand wire that plugs into the side of your alternator is likely broken and every auto parts store stocks those plugin wires with leads about 8" long for about $5.
Thread Starter
4th Gear
Joined: Jul 2015
Posts: 4
Likes: 0
Thanks for the input everyone! I will definitely check the heater/ choke fuse and move on to wiring if need be. I thought about ringing out the brown wire (if I can find it under the dash). They definitely didn't make these cars for anyone tall to work on!
The funny thing I can't figure out is, when I jumped the small post to the brown wire on the alternator, I got 14+ volts to the battery. But the voltmeter in the dash still read 0. Could it have anything to do with my problem?
The funny thing I can't figure out is, when I jumped the small post to the brown wire on the alternator, I got 14+ volts to the battery. But the voltmeter in the dash still read 0. Could it have anything to do with my problem?
Thread Starter
4th Gear
Joined: Jul 2015
Posts: 4
Likes: 0
Update!
I put a new plug on the alternator. Spliced it in with some good dielectric grease and shrink tube. Threw my voltmeter on the battery and have 14+ volts! The odd part is, I rang the plug out and had continuity. the wire must have been broken?
Voltmeter gauge is still reading 0. I'll take it out this week some evening and see if maybe I have a wire off. It has a new circuit as of last year. Thanks again for everyone's help! This is by far the most active forum website on the net!
Voltmeter gauge is still reading 0. I'll take it out this week some evening and see if maybe I have a wire off. It has a new circuit as of last year. Thanks again for everyone's help! This is by far the most active forum website on the net!
