RamDodgeSam

While considering installing the Transpo 8315 on my alternator I started trying to identify the switched field terminal but came up a little confused. With engine running, I get 12.5V on the bottom terminal, and 10.5 on the upper one.
With the key just in the RUN position, I don't see voltage on either terminal. I even removed the wiring harness to isolate them and I don't see voltage to either one without the truck running. Is this a problem likely related to my overcharging issues? Last I checked, I was getting 14.2V charging with just the stock PCM set up ( I don't have a regulator on the upper middle firewall like I've seen on some older trucks.)

Do I have a problem to track down or should I just put the orange Transpo wire to the lower termina, put the green one to the upper one, bend up that tab on the harness and go with it? OR do I need to add a switched hot wire to the lower terminal?
My strong suit is not auto electronics to be honest. more of a mechanical person, but i can get a job done once i get it sorted out in my head, so I'm seeking help. Thanks yall.

RamDodgeSam

I found the auto shutdown relay where the wire hooked to the J2 terminal (lower field stud on alternator) connects on the driver fender. I was able to read battery voltage at that wire momentarily as the key is switched on however, it only lasts a second. Is the relay faulty?

maybe368

I had an overcharging issue recently. There are really just a few things that can cause that like: resistance in the green wire to the vr. This is the one that goes to the ignition switch to read battery voltage. Resistance causes a low battery reading and forces an overcharge condition. My problem turned out to be the last 3 inches of that wire was as hard as a nail. The solution was a direct wire to the battery and a relay controlling the vr...Mark

oliver foster

Did the same thing to my '91.0 a year or so ago.
Same problem. Same solution.