72 Alternator Wiring
Melting Slicks
Joined: Mar 2005
Posts: 2,095
Likes: 299
From: Midlothian VA
So FYI: out of curiosity I tested the voltage at the connector on both my 71's last night.
Once you turn the plug around see if you get the same results.
Key Off and both wires plugged into the alternator: Term #1 (brown wire) = 0v and Term #2 = +12v
Key Off and probing the plug after removing it from the alternator: Term #1 (brown wire) = 0v and Term #2 = +12v
Key On and both wires plugged into the alternator: Term #1 (brown wire) = +4v and Term #2 = +12v
Key On and probing the plug after removing it from the alternator: Term #1 (brown wire) = +12v and Term #2 = +12v
Note: the black w/white tracer wire should ALWAYS be hot +12v as it is directly wired to the positive post of the alternator.
The brown wire should be hot only when the key is on.
Once you turn the plug around see if you get the same results.
Key Off and both wires plugged into the alternator: Term #1 (brown wire) = 0v and Term #2 = +12v
Key Off and probing the plug after removing it from the alternator: Term #1 (brown wire) = 0v and Term #2 = +12v
Key On and both wires plugged into the alternator: Term #1 (brown wire) = +4v and Term #2 = +12v
Key On and probing the plug after removing it from the alternator: Term #1 (brown wire) = +12v and Term #2 = +12v
Note: the black w/white tracer wire should ALWAYS be hot +12v as it is directly wired to the positive post of the alternator.
The brown wire should be hot only when the key is on.
Thread Starter
Drifting
Joined: Nov 2000
Posts: 1,390
Likes: 39
From: North Brunswick NJ
Thanks for all your analysis, I did change the plug around this morning, with the following results:
Blk&white wire , Hot with the ignition on an off
Brown wire, Hot with ignition on, no voltage when ignition off
Engine running 14.6 volts at the battery.
So it looks like it is working fine in the garage. I just need to watch for overcharging and battery drain. It is to bad I made so much out of nothing. Thanks for tolerating my incompetence.
Ed
Blk&white wire , Hot with the ignition on an off
Brown wire, Hot with ignition on, no voltage when ignition off
Engine running 14.6 volts at the battery.
So it looks like it is working fine in the garage. I just need to watch for overcharging and battery drain. It is to bad I made so much out of nothing. Thanks for tolerating my incompetence.
Ed
