Oh, and if the auto harness doesn't work, maybe we'll try to swap out the PCM. We'll just have to see what combination works best.

 

I would swap the manual PCM into the truck first and see if that fixes the romp. My bet is that it will and that the cruise controls will work flawlessly as long as you install the safety switch on the clutch pedal.

 

x2 For sure.
It doesn't need that. I really believe that the only bearing that switch has on anything is preventing starts without the clutch pressed and disengaging cruise when the clutch gets pushed enough to close that switch. I could definitely be wrong though.
Do you know if cruise control has to be "activated" or is hardware in a PCM? Or is it only a matter of having the cc module in the truck, the controls on the wheel, and proper wiring? I've heard so many things about what all is involved in cruise control functioning and don't know what is right.

 

My understanding of it is that all you need to add to have cruise control on a truck that didn't have it from the factory is the wheel pad that has the buttons. I may be wrong, but that is my understanding of it. I would still want the switch on the clutch for the safety of not being able to start it in gear and so you cannot pop the clutch and have the engine run away while it tries to maintain the CC set point. It's just my personal preference, but I wouldn't want to have it be unsafe in case someone else would happen to be driving it.

 

The clutch safety switch is installed. Maybe we'll just swap the PCM's out first before we go banging our heads against the wall figuring out the wiring. Thanks guys. We'll let you know how it goes.

I'd still like to see the wiring diagram, if anyone knows where to find it.

 

There is no communication between the PCM and the ZF5. The only thing electrical on the ZF5 is the reverse light switch, and that's strictly its own circuit. But that's the problem with the auto PCM. IIRC, it romps because it doesn't "know" you're in Park or Neutral. You could connect the tranny switch from the auto, and "shift" it into Neutral, and that would probably make the romp go away. But I'd bet that if you did that, the PCM would also assume you're always in neutral, and wouldn't enable the cruise. So yeah, a manual PCM is the way to go. You can always wrap the auto PCM in aluminum foil and bubble-wrap, and stash it in the basement, to use as a disaster recovery PCM after an EMP caused by a solar or nuclear event <insert "tinfoil hat" smiley here....>.

The clutch switch DOES affect the cruise. It's essentially two switches (thus, four terminals). The two terminals closer to the firewall are for the start lockout, and those contacts close when you push the pedal all the way down. The two terminals closer to the seat are for the cruise, and are closed with the clutch pedal all the way up, and open (to interrupt the cruise) when you first start to move the pedal. Automatic trucks have a block plugged into that connector, that closes both circuits. If you have the switch on the pushrod, and plug that connector in, both the cruise and the start circuit should work just like from the factory.

There's no single wiring diagram. The EVTM is a few hundred pages. Just the Powertrain Controls section, for just the 7.3, is something like 6-8 pages. Not sure about the E4OD section; starter section is all on one page, IIRC.

 

Well...FIL just called me and said he called a place to see if he could find a PCM, because he will need one if I use the one out of our donor. The guy looked it up and said there were 6 different ones for 94...some that were for just 94, some that were for 94 and 95, etc. I guess things changed with each different configuration of the PCM, including the OBD (on board diagonstics). So my question is, will that negatively affect the way my 7.3 runs if I use the old PCM? I mean, any refinements that Ford coded into the 97 PCM would be lost, and I would basically be operating in 94 mode (if I use the 94 PCM). The question is, are they really interchangeable?

 

just send the money and send it in to Dp (only tuner I am personally aware can re-flash, I am sure there are others out there) and solve the problem all together. No need to even worry about differences.

 

Yes they are really interchangeable as long as they are all for OBS trucks with the same transmission. But yes, there are different PCM codes and they each are slightly different in their programming, but any of them will work. My DD is currently using a 96 PCM to run a '95 motor and it works fine.

Or, like Mike said, just send the PCM to DPTuner and let them flash a new tune to it. I think you will be impressed with how well it runs with their tunes on it.

 

Very good to know!

 

This might shed some light: PCM Codes - 1994-1997 Power Stroke FAQ

 

Fortunately for me, I'm the only driver of my truck. I like being able to lean in and start it with no clutch and let it warm up. I do keep a clutch-starter switch in the glovebox though because once or twice a year the woman may take the truck and then I just pull the auto plug and put the switch on for her.
I absolutely agree that it affects active operation of cruise control. I even said the same a few posts ago(although I said it closes the switch instead of opens to cancel). What I meant by "It doesn't need that." is that the switch is not mandatory for cruise control to be engaged. But then you are REQUIRED to use the wheel pad button or tap the brake to disengage.
After I finished my swap I put the manual PCM from my donor(95 PSD XL no cc) into my truck(sig). I drove it with the c-s switch installed and no cruise contol function. I swapped in the jumper for the auto and no cc function. Then I went home and threw in my auto PCM and went for a drive. The cc activated appropriately and disengaged with the brake and buttons. I didn't try the clutch because I feared the auto program would let the engine runaway. Anyway, point being, that the cruise unfortunately failed to work simply because I had a manual PCM and the switch installed. I did not try, however, a manual PCM with the PCM harness spliced as it is now for the cc to work with an auto PCM and manual programming.

Phewww. I hope that makes some sense.

 

It would have let the engine run away if you had tried. PLEASE don't ask me how I know.

 

my lope was fixed with my ts chip i had beans buren it to trick the pcm down side i lost crusie but roomer has it oriley can have them flashed

 

Why not just leave the switch on the pushrod? Then just use the auto jumper when you drive it, and plug in the switch when she drives it.

I always bypass this switch on my passenger cars. On at least three occasions, I've been able to "push" the car out of harm's way with the starter when they've broken down. I still keep it in place with a 6000-lb truck, though. ** Note: whether you jumper it or use the switch, you can unplug it for a poor-man's kill-switch when you park it in, er, sub-optimally secure locations.