PCM For 1991 W250 with 5.2l, 4wd and manual transmission

Rug_Trucker said
Do you have a 91.5? If intercooled that's what you have. One wire alternator with built-in regulator. Also probably controls the a/c too. Go to the cummins forum go to the 1st Gen non power train section.

Could be 91.5. We've had issues just to get the correct alternator. But I think you are correct.
I'll look into that as well. Thanks