I mean to say 4x4 lights are in 15 and 16, not backup lights. I think we have that figured out. Looked on the auto harness, and they are in 5 and 6. No worries there. The problem now is the clutch tan/blue wire. We tested for continuity on every plug in the PCM, and there is none at all. We found why - that wire runs into the big plug beside the PCM in the firewall (big rectangle) and stops - there is no pin in the male side of the plug (the side inside the engine compartment). We found where the tan/white wire (Pin 29 in the PCM - for the "transmission control switch" on the auto and the "clutch position sensor" on the manual) goes from the PCM to that same plug, but we can't figure out where that tan/white wire continues under the dash. We're thinking those need to be connected to complete the circuit so the PCM can see the clutch position sensor.

Any suggestions?

 

As promised, time for the pictures from yesterday.

New tcase in and giving a drink:



Bolting in the new center hump and putting the carpet back. You have to cut the hole, but it's not too bad. A good, sharp utility knife does the trick:



New carpet and shifter in place:



Seats reinstalled:



Here's the key release from the manual installed, then the upper steering column cover from the manual truck. The lower portion of the steering column cover is the one out of my good truck (automatic), since it is tilt wheel. This way, you can have your cake and eat it too!





And a few of the new pedals and shifters:





And the aftermath. Here's everything we pulled out...unless we forgot to throw something in there



This evening, we used all the good advice we found on here and worked on the wiring for the 4x4 lights and attempted to get the cruise control set up:

For the 4x4 - The advice we got worked perfectly. The 4x4 lights on the manual trans wiring harness are in pins 15 and 16, but they need to be moved to pins 5 and 6. We took the plug apart, moved the pins, and it worked like a charm.

For the cruise control: The wire from pin 29 in the PCM is supposed to lead to the tan/blue wire on the clutch switch. It does not in the automatic. It actually goes up to the automatic shifter and connects to the O/D cancel light (It took a while to figure this out). We jumpered this wire from the plug where the automatic shifter was, down the steering column and connected it into the blue/tan wire from the clutch switch, so this should have made all the proper connections, as far as we know. We took it out for a test drive, and the cruise didn't work. Any further advice on this would be helpful. It may not work, but I think it's a mystery if the PCM acutally determines whether the truck has cruise or not. If that is the case, then maybe our PCM will not allow cruise to work, since the donor didn't have it. We will have to continue research.

We appreciate all the help that you guys provided and the great information that you shared for this project. What a great resource! Hope someone learns from our experiences as well. Hopefully we can figure out the cruise control sometime soon.

 

I second that. Thanks everybody!!!

 

Nice job guys. Feels good doesn't it?! I was happy to be able to drive it but the little issues like the no start and cc drove me freaking nuts until I got em worked out.
I really think it just has to be something with the PCM. What? I have no clue. My best guesses are it is missing some special hardware altogether because the original truck had no cc or that it is like high idle on the new dodges - some have it and some "don't" but you can get it "turned on" by the dealer. I wish somebody had access to a PCM from a manual with known cc to try it in a swapped truck.

KRIS try STEVE'S!!!

 

I suppose if you think it is still a function of the PCM, you could always swap the auto PCM back in place and try the cruise. I know it will lope idle, but at least you would know then whether you have a wiring issue with the cruise or if it is the PCM.

 

But with there being a difference in output through the pins of auto vs manual pcms it still may be a wiring issue causing the manual pcm to not work. If his cruise worked as an auto then it will still work with the original pcm without wiring changes.

 

So is the thought that the wiring could be preventing the cruise from working as well? I would think that if he has the wiring right for the manual transmission harness to communicate with the auto PCM then it would be communicating with the auto PCM as well. See what I mean? Or am I confused? I guess my though process was that if the pins have been re-arranged to send the necessary signal paths to the PCM through the manual transmission harness then the auto PCM should work. If the wiring isn't right the cruise won't work with the auto PCM either. Right?

 

If some wiring got messed up I guess. If the wiring is original it will work like it always did. But since there wasn't a clutch in there before it won't respond to clutch manipulation now. Nothing about the trans swap has anything to do with what the unflashed auto PCM directs to happen. It's business as usual for it. All it evidently knows is that the TRS is not sending so we guess it's romping because of that(although mine did not romp once). Aside from the romping the truck runs the same including cruise control.
If you flash the auto PCM to manual programming then you have to adjust the wiring for the cc to work.
No one yet knows how to make an actual manual PCM AND cruise cruise control work together because either: 1)The PCM has to have cc "in" it in some form or fashion to start with for the cruise to work in a truck. Whether it is built into the PCM or has to be "activated" by someone. 2)The PCMs have no bearing on cc aside from the different pin functions(ex. OD cancel switch vs clutch-starter switch communication) and we've not tried the manual PCM with the proper wiring reconfiguration.
It would help SOOOOOO much if someone would say with certainty what, if any, bearing the PCM has on cc function. I have no idea where else to ask. I've asked a ton of people all with different answers. Some not very sure and others positive(who turned out to be wrong).
Tomorrow I will pull the PCM from my 5 speed F350 and put it in my 250. HOWEVER, the 5 speed DOES NOT have cc. We'll see what happens.

 

Alright guys. The cruise control now works. What fixed it?---Installing a new third brake light bulb (which was burnt out in my truck). I'm sure you've probably read somewhere on here (and other sites) as I have that the brake light bulbs will cause crazy things to happen (like the E4OD to throw codes and in this case, the cruise control not working), and replacing them seems to fix it. Well, at least in our case, it does.

What is for certain:
1) Our '94.5 donor truck DOES NOT have cruise control
2) The cruise control was not working last night, with the PCM from the donor truck in my XLT, which has the pad for cruise control, and the cruise control was working properly before the swap
3) We decided to try replacing the third brake light bulb on my truck, just for S#$%s and giggles. THAT'S ALL WE DID. The cruise control now works. We made no further wiring modifications other than the ones previously posted. To recap - we ran a jumper wire from the tan/white wire that runs up to the automatic shifter for the O/D cancel switch, down the steering column and connected it to the tan/blue wire on the clutch interlock switch on the clutch master cylinder push rod. Effectively, this gave continuity from that tan/blue wire in the clutch interlock switch to Pin 29 on the PCM, which is where it is supposed to go. So our wiring was right last night....but the third brake light blub being blown was preventing the cruise from working.
4) All cruise control functions appear to work properly, including the cancellation of the cruise by both the brake and clutch pedals.

This may sound as crazy to you as it does to us, but we are 100% positive of all the facts.

So...that leads us to believe that the PCM DOES NOT determine whether the truck has cruise control. We're assuming that if the truck has the cruise control functionality, then a PCM from a truck without cruise control will still allow cruise to function, provided that the proper wiring modifications to be made connecting the clutch interlock switch to Pin 29 on the PCM.

We still have the question, which doesn't really matter at this point: Where in the heck does the tan/blue wire go in the auto trucks (it is not even in the PCM harness)? Does it dead end somewhere? The plug for the clutch interlock switch exists and is capped off in the auto trucks. ???

If anyone wants a more detailed explanation of the wiring modifications we made, let me know. I think this is pretty detailed, as the mods were fairly simple (one wire).

 

Good to hear

 

Sweet! Glad you got it all figured out. That pesky third brake light is a strange one. It is amazing how many different issues that thing can cause. Glad you got it going. I don't have to eat that crow after all.

 

Awesome man! I'm glad yall were able to get that figured out. Isn't there a cruise control module or something in the truck? I guess all it takes is that, the horn pad, and wiring. Good job guys!

 

Nope, the PCM _is_ the cruise "module". Think about it -- what would a separate module control? It's not like a gasser with a mechanical throttle, which would require a module to operate. Since our trucks are drive-by-wire, the PCM just feeds the right fuel commands to the IDM the same way it does based on pedal position. That's also why the pedal doesn't move with the speed when you're on cruise, like on a gasser.

 

We used the pcm from a truck without cruise control and the cruise works. I think what controls the cruise is the speed control amplifier assembly.

 

Rebilld and I have discussed this at length - and based on the wiring diagram he posted, along with our experiences with the PCMs, we don't believe the PCM is the controller of the cruise control, entirely. We think that it definitely plays a part, but if it were the only thing that determines whether the truck has cruise or not, then we shouldn't have it, because the truck that the PCM came out of didn't have it. You can't deny that fact (well, WE can't - none of you have really seen it, so I guess you can deny it all you want!). Unless, for some strange reason, some of the manual PCMs were built with the CC functionality and put into XL trucks with no CC, then we just happened to get one of those. Then some manual PCM's would have to be built without the CC functionality - because there are plenty of guys out there who've done this and do not have cruise control.

It makes sense, based on that wiring diagram, that the "speed control amplifier assembly" in the lower left corner would also play a major part of the cruise control functionality. The PCM works with that, sure, but we don't think that it IS the "CC module."

I find it weird how this is such a big mystery. You'd think someone would know for sure. Either way, we took a PCM from a manual truck with no cc and now the cruise works in my truck. That should tell you it's not the PCM. I think the wiring is the key - if you haven't made the proper wiring mods, then your cruise won't work no matter what! We learned that the hard way. Even the third brake light bulb...