Topic: Alternator Terminal Identification (Charging Issue)

[82juguete]

I've been plagued by an ongoing charging issue. Truck is a 1982, originally had a 22r, but I swapped to a 1980 20r. When I swapped the motor I kept the alternator from the 22r so that it stayed kosher with my existing regulator/chassis loom, etc.

The regulator has the irregular oval plug, with 5 blades. I'm hoping someone has the same setup and can identify for me the wire that I've realized was torn clean off at some point. The attached diagram should help explain what I'm talking about. Note the wire colors that I was able to best identify don't jive at all with any of the FSM wiring diagrams I have referenced.

I'm hoping someone can help me out with a color, or even better, the destination of where this wire goes (in regards to the alternator or vehicle loom)...Thanks.

[82juguete [OP]]

I'm far from a wiring guru, but it seems to me that the attached schematic shows my configuration. External reg with 5 wires. Correct me if I'm wrong on this, but I'm interpreting the wire colors to be Red, Yellow, White and Green, meaning the one I'm missing is (B) or black (or blue?)

This diagram also shows that it's one of the integral wires going directly to the alternator. This would be a clear cause of failure to charge if this is the case. I will have to peek inside the wire loom and see if the mystery wire broke off inside somewhere... seems like a long shot but we'll see.

Is my interpretation completely off on this?

[82juguete [OP]]

I just took a quick look and I noticed that the wire in the pigtail coming off the regulator that lines up with the one I'm missing is black. (All others are white with colored indicator stripes)

I'm starting to thing the missing wire may be a ground.

Can anyone confirm this?

[tgmaul88]

black ground, ill go look at mine

[82juguete [OP]]

Thanks. Broken ground would be the best case scenario.

[82juguete [OP]]

I temporarily grounded the wire in question. Either the wire is not a ground or the problem lies elsewhere.

I put a fully charged battery into the truck and tested the voltage. 12.93 volts.

Started the engine and checked the battery voltage while it ran. 12.5 volts.

Increasing the RPMs, blipping the throttle had zero effect on this number, so I'm still searching.

[82juguete [OP]]

Did some more testing. Pulled my attention away from the regulator at the moment.

The alternator doesn't appear to be charging (no magnetic field on the back of the case when running). But I have no reason to believe it's bad yet.

Took the voltmeter to the harness plug that the alternator plugs into expecting to find and ignition hot (ign), a constant hot (sense) and the lamp wire.

All that showed on the meter was the ignition hot.

My plan now is to run a jumper wire from the battery to the sense terminal on the alt so that I can truly test the alternator's functionality. Problem is, I can't determine which terminal is which on the back of the alt. For the record, my plug type is like the one shown below.

[82juguete [OP]]

Could someone help me label the above with (L) Lamp, (S) Sense, and (I) Ignition? Thanks.

[82juguete [OP]]

Found another clue and answer to my above question. I'm going to jump power to that sense terminal and see if the alternator operates correctly then. That should tell me if a fusible link blew on that sense wire or something.

[GONZO97]

so whats the verdict? I know you sent me that video today but how are things going? update!!!