TwoJeeps

Have I got one for you. I have looked thru every forum I can find for the past 6 hours and no one has a write up about it. The closest I could find was a mention about 1996 being a 'transitional' year for XJ's. I have a 96 XJ Sport that had it's voltage regulation go out. I put in a new Grand Cherokee alt. and still did not put out any voltage. I replaced the battery temp sensor to no avail. Now the pinout I found for 96 to 99 PCM's shows a 'Generator Driver' function at pin C25, and I have yet to find a schematic that shows this wire. Nor do I have one in my wiring harness. They do show the 'Generator Field +' connection (B10) which should be what the PCM uses to monitor output and set the 'GEN' light, voltmeter indication, and codes. And the generator driver should be the connection that is controlling the output. The 97 Sport & 99 I looked at in the junkyard has a driver wire. So my real question is, does anyone have any direct experience with the transition between internally and externally regulated alternators in the XJ's? I'm sure if I pull the wire from the 97 and route it the same way in mine, it'll fix my problem. But as I said earlier, I cannot find this wire in any schematic.

93gc40

Voltage regulation is done INSIDE the computer on all XJ and ZJ. So if you lost regulation you'll need to replace the computer.

freegdr

Wire in a external voltage regulators another option .

TwoJeeps

I know that's right. The difference in wiring threw me for a bit. I was at the junk yard to get a PCM. Found out some guy from several states away came thru and bought every control module from 1995 and newer out of the Jeep and Toyota SUV's. Thanks for the inputs though.

TwoJeeps

Ok. New alt, new PCM, checked wiring/cleaned posts. Still no regulation. Going to remove the alt and take it in for testing. ANY ideas? Does the black molded piece have something in it that goes bad? I'd really rather not patch in an external regulator. It's just me. Thanks

freegdr

The black box on wiring is just to help locate the correct wire at factory when being assembled . Have you confirmed powers getting to alternator ?

freegdr

If alternators not getting power it will never charge........

freegdr

http://www.wranglerforum.com/f210/al...ood-63611.html

5-90

Possible, but it will throw a persistent CEL/MIL if you do, since the PCM will note that the internal regulator isn't doing anything.

If there is a workaround for this, I'm not aware of it.

torque062

Have you checked if the fusible link is still good? I don't think that has been mentioned yet

TwoJeeps

Thank you for the link. I'm going to try that.