Engine/Transmission (1994 - 1998) Could it be the PCM?

[Mactruck]

Few weeks ago I posted a question about Alternators for a friend of mine with a 96 12 valver. See post here



Well he replaced the Alternator and he is getting 0 juice from it. He suspects the PCM is not sending the juice to the batteries.

All battery connections and batteries are good and the GEN light is still on.

What do you think. Could this be the next solution? and where is the best place to get one?

I know it's not a cheap part but I thought I would run it by you guys first.

 

[Midnight]

I didn't see it posted in any of the other posts, but be sure to check that the fuse isn't blown. Good luck.

 

[Mactruck]

Sorry, He did say he checked all the fuses.

 

[illflem]

I'm not going to say it's the problem but Napa can get you a rebuilt PCM, not sure how much they are but they do give you $200+ for the old one.

 

[CumminFast]

I heard NAPA alternators kinda suck. I know the Advance Alternators suck, I am going to try AC Delco next.

 

[bd450]

My service manual show the alternators field coil is driven from the PCM. So it could be the PCM.



I've been inside my PCM to replace a blown trans pressure regulator transistor and they are repariable/rebuildable to a certain extent. If everything else on the truck works ok it probably just blew the output stage.



Took me 8 hours over 2 weeks to get it figured out and get replacement transistor and replace it. I wish Sams Fotofacts had a schematic for the darn thing. Would save tons of time and guesswork. I repaired a PCM for another TDR member that had the same problem and never found out how his worked. He had already bought a new PCM so he probably never even installed the repaired one to check it out.



Sorry, I'm not doin anymore PCM repairs. No spare time for it.



If you had the time and ability you could try to add on an external voltage regulator and wire it in place of the PCMs field driver. That would replace the function of the PCM for that one circuit.



Thats what I'll be attempting if mine ever takes a dump. Would save hundreds of $ over a rebuilt PCM.