Manual Transmission on a A/T Harness...

[Jake Harsha]

Hey,

I'm in the final stages of swapping an LQ4 out of a 2007 Silverado 2500 into my old Jeep YJ. I have an NV4500 in it and so I had the computer re-programmed using whatever stock programming is used for a LQ4/NV4500 (minus VATS, Torque Mgt., etc.).

I've found a little difference in the physical wiring harness that has necessitated adding a wire to the PCM for the clutch position switch (that I'll have to install on the clutch pedal/linkage to get the cruise to work right). It's pin number 35, Gray Wire, circuit number 48, CPP Switch Signal (M/T) on C1 into the main PCM. (There wasn't a wire there because the donor truck was an AT, but there is now)

I have a couple of questions regarding this:

1. Is this clutch position switch a normally open switch that would connect the wire to +12V when the clutch gets pressed or a normally closed switch (like the TCC brake switch for the cruise control) that has +12V flowing through it all the time EXCEPT when the clutch is pressed?

2. Are there any other "gotchas" I'm missing when trying to get an A/T harness to function correctly with a manual transmission?


Thanks!
Jake

[zebra]

subscribed, in case this happens to me this week...

[r6z4o6]

I would like to help ya out. I have electrical manual for 2001 trucks. I see circuit 48 on the CPP connector, and the PCM, but can find no info about what happens on it.

The only thing i can find is (hot in run) BRAKE 10A goes through stoplamp switch via terminal D/BRN/441 into stoplamp switch, then out terminal C/PL/420,(stoplamp switch cuts the circuit when the pedal is pressed) then into terminal A/PPL/420 of CPP and out B/BRN/WHT 379 into terminal D of the Cruise Control Module.

The brake and the CPP both CUT 12v to the Cruise module.....I have NO IDEA what happens on circuit 48 or the PCM!!!!

[Jake Harsha]

I would like to help ya out. I have electrical manual for 2001 trucks. I see circuit 48 on the CPP connector, and the PCM, but can find no info about what happens on it.

The only thing i can find is (hot in run) BRAKE 10A goes through stoplamp switch via terminal D/BRN/441 into stoplamp switch, then out terminal C/PL/420,(stoplamp switch cuts the circuit when the pedal is pressed) then into terminal A/PPL/420 of CPP and out B/BRN/WHT 379 into terminal D of the Cruise Control Module.

The brake and the CPP both CUT 12v to the Cruise module.....I have NO IDEA what happens on circuit 48 or the PCM!!!!

Thanks for looking... One thing I've noticed about these is that pin-outs change quite a bit from year-to-year, so whatever pin 48 was on an '01, it might be something completely different on an '06. (I started out with '04 pin-out list and and there were so many differences I had to bite the bullet and buy the right one from alldatadiy.)

However, no matter what pin it's on, I'd bet it's functionality wouldn't change... I've been trying to decipher the inscrutable wiring diagrams on alldatadiy and getting nowhere so I figured I'd make an appeal for help.


Thanks again,
Jake

[r6z4o6]

I hear ya. The PCM pinout on my '01 says EXACTLY what your says in '07. However, on the page that shows all the Cruise Control circuits, mine shows NOTHING going into that pin on the PCM.

[SBL]

My 2002 Silverado schematic for the 'clutch' switch shows a brown/white wire going from the cruise control's 'stop lamp switch input' to the Normally Closed terminal on the clutch switch and then a purple wire connected to the other terminal on the clutch switch going to the 'brake switch', which is connected to 12vdc thru a 10a fuse. Pushing in the clutch de-activates the cruise control by taking away it's power source.

I don't see any of this connected to the PCM... I do see what they call a 'mid bussed electrical center' which for this swap can be deleted.