PCM pinout

Thank you! That helps a lot. I'm trying to fix the alternator control circuit to provide battery charging, but I can't seem to find the correct circuit diagrams.

Thanks for your help! The history is: 1) The battery drained out and read 10.5Vdc so I replaced it. 2) The battery read 12.7Vdc running and off, so I removed the alternator and it bench tested good at O'Reillys auto parts. I reinstalled it and still no charging. 3) I checked the wiring from the alternator to the PCM and didn't find anything wrong (alternator pins 1 and 2 checked good (0.2 Ohms) to PCM brown plug pins 2 and 40, and to no other pins). With the PCM plugs removed and the alternator and battery reconnected (read 12.4Vdc), the white plug (now with your info I know that's C1) had solid grounds on pins 49, 50, 51, 52, 53, and 72, and 12.4Vdc on pins 80 and 96. The brown plug (C2) had 12.4Vdc on pin 40, and pin 2 still reads continuity to pin 2 on the alternator (no voltage). So I ordered a PCM. I'll continue in the next reply.

4) I got 2 bad PCM's on line, pre-programmed to vin, but had other problems. One DID make the alternator work, so I had that one reprogrammed by the dealer. It fixed some problems, but not all. 5) So I got a new Mopar PCM (and programmed) from the dealer. Still not charging, but no new problems. They swore the problem wasn't with their PCM. 6) So I replaced the alternator even though the original bench tested good, and still not charging. Alternator pin 1 reads 2.0 Ohms to ground with engine off and 3mV with engine running, pin 2 reads 12.4Vdc with engine off and 9.4Vdc with engine running. So I replaced the alternator again (thinking it could have been bad from the store) but STILL not charging. The battery gets down to about 11.5Vdc with the engine running before I recharge it to continue troubleshooting. 7) That's when I found your site on line and finally got the right PCM pinout and charging diagram! I'm not convinced that the PCM I got from the dealer is good, but it still could be the alternator wiring to the PCM (I'll recheck the resistance) since the pin 2 voltage drops to 9.4Vdc with the engine running, or the B+ input into C1 pin 96. The bad PCM that does operate the alternator could have bad monitoring, so it would likely over charge the battery. Thanks again for your help!

Oh yeah, will also check red alternator wiring to battery. Thanks again. Should be back on it today.

Okay, still no joy.
Rechecked wiring with alternator connected and battery terminals disconnected:
Alt pin 1 to PCM C2 pin 2: 0.1 Ohms,
Alt pin 2 to PCM C2 pin 40: 0.1 Ohms,
Alt pin 1 to gnd: 2.7 Ohms,
(C1 pin 50 = gnd = batt black lead)
Alt pin 2 to gnd: climbs - 2k to above 10k. Just keeps climbing.
With Alt disconnected:
Alt pin 1 to gnd open
Alt pin 2 to gnd open
PCM C1 pin 96 to red batt lead: 0.1 Ohms,
Large red Alt lead to red batt lead: 0.5 to 1.0 Ohm.

I'll have to try again tomorrow.

Okay, I see it is a problem for the sense line (Alt pin 2) to drop to 9.4Vdc when the engine is running. Your circuit operation description says the Alt output terminal is internally connected to the pin 2 sense output to the PCM. There must be resistance in the alternator output terminal to the battery positive terminal, dropping the 3Vdc
(or the Alt conn socket to the Alt pin 2, but it looked solid).
I should be able to get back on it today.
Thanks so much for the diagram, circuit operation description and PCM pinout. Huge help!

Okay, still not solved. I was fooled by resistance readings with the PCM still connected. Recharged battery, disconnected PCM C1 and C2, and reconnected the battery:
Alt pin1 to C2 pin 2: 0.1 Ohms.
With 12.7Vdc put on Alt pin1, C2 pin2 lights the test light.
Alt pin2 to C2 pin40. 0.1 Ohms.
12.7Vdc to Alt pin2, C2 pin40 lights the test light.
PCM C1 pin 96 12.7Vdc & lights the test light.
I'm finally convinced that this wiring is good.
I found a Remy tech service bulletin on Chrysler charging systems that has more info on these alternators, (at autoprollc. Com website menu under Service Resources under Technical Bulletins). It turns out the sense output (alternator pin 2) is a Kelvin sense circuit that should have no current on it, but it does have a 2.4k Ohms resistor in the alternator to protect it from shorts to ground. That's where the 2.333k Ohms came from, and the voltage drop on alternator pin2 when the engine is started.
I'm not convinced the new PCM is good, but apparently there is a 5V turn on voltage to the EVR circuit when the PCM determines it should be turned on.
I haven't found the inputs the PCM requires to determine that the ignition is on and the engine is running. I haven't heard of any other requirements. Thanks for your help.

Yes, the Dodge dealer ordered it and programmed it. Sorry, I haven't been able to get back to it. I was wondering if one of the 5V supply voltages on the PCM pinout is required to turn on the EVR circuit? Or if there is some other sense or sensor input the PCM needs to turn on the EVR circuit?

Oh, I did replace the alternator. Since it still didn't charge, I took it back and got another one. Still not charging the battery. So with the second new alternator I unplugged the small alternator connector and monitored the battery voltage while I jumped 12.4V battery voltage to pin1 on the alternator. The alternator turned on and I disconnected it when battery voltage got to 16V, so the alternator does work if the regulating voltage is applied. The only question is why the PCM isn't putting out the EVR voltage.

No, I haven't gotten a scan tool yet. Looks like a necessity these days.