Another charging issue

[Diesel Nut]

Ok, I am stumped.

Charging high, like 15.2 or so. Voltage will fluctuate visably on the gauge and at night you can see it in the lights. Truck not running its fine, 12.5 battery voltage.

Swapped out the alt. No difference

Swapped out the Regulator. No difference. Ordered new reg. Nope.

Swapped PCM. Got worse. I think the PCM was mislabled by the gent I bought it from, it was throwing ASD Relay codes and my truck doesn't have the ASD Relay.

So, I am thinking its the PCM. I have other issues with the PCM as it is. The PCM is supplying 4.98 volts to the TPS Supply wire, AND the signal wire. So, there is why my transmission won't shift into OD on its own (I have a switch on it).

Any ideas on the charging? Anyone opened a PCM up to repair it?

[Oddfire]

Where did you get the voltage reg. from? Wasn't a new one from Napa or Shmucks was it?

[Diesel Nut]

The new one is from Napa. I know they aren't as great as OEM, but I expected it to at least temporarily fox the issue.
I have tried running a ground wire from VR to battery, to body and to motor. 3 different VRs, same problem with all 3. Makes me lean towards VR isn't the problem.

Did some number checking and PCM I bought was in fact for a 93 and not a 91.5, so that explains alot there. . . . .

[Richie O]

If you have a voltage regulator then the pcm should have nothing to do with voltage regulation like the 92 and 93's. Maybe Im wrong. I would agree that a 93 pcm would not work correctly on a 91.5 but still fail to see where it would change voltage. I assume the voltage regulator circuit does not go through the pcm. Philip, what do you think? ( he knows better then me ).