BKTC

Checked "sticky" section and saw a couple that apply but was wondering if anybody had completely eliminated the PCM on a '92/'93 CTD. The PCM contols alternator charging and ABS....What else, and is there a way around the PCM.. This icon is for me...............

Billy

Gots_a_sol

I imagine it controls cruise as well. I think it works the overdrive as well in an auto truck.

monstr250

you guys are both right. also i believe it controls you A/C. i disconnected mine on my last truck. external regulator of the charging, rocker switch to ground to control overdrive and a rocker switch for a/c. never put anything in for the cruise control but i suppose you could set up a manual locking throttle cable.

mhuppertz

You would have to switch over to all mechanical systems unless you have the chops to make your own PCM. But why?
Even your speedo is controlled by the PCM. It would be a nightmare I think.

monstr250

when i bought my 92 it was all set up with switches and an external regulator. i felt it was a nightmare. i saved up the couple hundred bucks for a new one from the dealership. it was really nice to have everything working again till the computer took a crap on me again about a year or so later. switched back to all switches and regulator and never had anymore problems. to each their own. both ways work, its all about what ya like.

BKTC

monstr250

When you went with the switches did your speedo work? If not, could you replace with a speedo cable from an earlier model and eliminate the "electric drive". Probably need a new speedo as well though.
Just seems like some stuff is getting hard to come by and expensive to boot.......I'd like to know I could keep the truck running without the PCM. Also I could live without the Cruise.......maybe even the speedo

Billy

Santaclaus

Somewhere on here I read that the ground for the speedometer goes through the PCM, and you can find a wire and grounded in supposedly the speedometer will continue to function. I also read somewhere that someone cooked up an external 5 V power supply to his PCM, and it started to work again. Though I cannot find that post. I have thought about getting a mechanical cruise control from an older vehicle and putting our electronic speed drive after its mechanism. Seems like it should work. All the rest can go back to the 1990 and older truck system. You can run a pressure switch for the overdrive along with a cargo switch in the care is also covered in the stickies. Just my two cents, Mike.

monstr250

To get back to you. my speedo did not work with out the pcm. easy solution would be a gps which displays vehicle speed. For normal driving I've remembered what speed Im at depending on the gear and rpm. the difference in price for switches compared to another was the way to go. most of the stickys will explain how to set it all up on switches. if you ha any other questions let me know.

GIT-R-DONE

Anyone know what pin on the PCM is the ground ans supply wire for the Speedometer?

My pcm is junk as well, just hooked up an external VR and all is fine now, other than not having cruise and speedo , but I just use my GPS for that.

carrnutt

Your GPS has a Cruise function?

Does this help?




I would imagine there is a good work around for this. It may involve some older, pre PCM parts though, like Santa mentioned. Also, would it not be possible to use a cable driven speedo, like the prior years?