Pcm
There are several options as to the PCM. One solution is to wire your truck like the 89s. They don't have a PCM and to my knowlege, no one has ever had a problem with that. I bought an 89 just to get the wiring setup for my 92 with automatic. I have not completed the conversion for a couple of reasons but will definitely do so before driving the 92 again.
Whenever I drove it, if I ever went more than one hundred miles west (yes West) from Georgia, it would start acting up as to overdrive. By the time I would get to Miss, it simply wouldn't go in OD. Texas and beyond, no alternator or AC. As I returned home, it would begin to work and by the time I got back to Montgomery, it would work correctly. To heck (you may add your favorite expletive here) with a Piece of Crap Mother that functions like that. This happened enough that I wasn't dreaming on this. Other directions were ok but the OD would always shift in and out at 52 mph. I spent hundreds on TPS and speed and axle sensors and still no proper function. Suncoast tells me that they can make the transmission work like it is supposed to but I am simply going to put a switch on the shifter and control the OD myself.
I have talked with an electronics guy who says he can furnish a switch setup that will cancel with the brakes and zero out when the truck is switched off. I have already changed the wiring so that the AC isn't optional to the PCM and also the alternator charging. In short, the Piece of Crap Mother is still on the truck but no longer in charge of anything.
THe only other thing that I know of under the command of the PCM is the switch on the oil temp that disallows OD when overheated or till warmed up. I have sense enough to handle those things for myself. A PCM on a diesel truck is an absurdity. If it is really needed, then Dodge should have provided a system that was reliable under the conditions of the real world. I believe it may have been added in 92 with the automatic OD because of some stupid buracratic notion in congress.
Boy I feel better venting about that Piece of Crap Mother.
James