Hoping 4WD or one of the other Cat gurus can help me out. 1995 378 with a 3406E. No jakes, no cruise. One of the clutch switch wires does not have continuity from switch back to ECM. Do these two wires go straight from ECM to clutch switch or do they route into the cab also? I am getting conflicting answers from different people. I am sick of not having cruise control and will part with the $800 for a new ECM to cab harness but want to make sure it will fix it and it's not a problem under the dash.

CAT service manuals only give us very generic OEM wiring diagrams. Truck manufacturers route their own wiring and looms how they wish.

Note: you can see that "Sensor common" (pin 29) goes to lots of sensors, and that (pin 24) is going to "clutch switch". (this completes a circuit)

Have you tried a "temporary by-pass wire" and see if the jakes and/or cruise switches (or called PTO switches @ 0 MPH) work?

 {I don't see the need for a whole expensive OEM wire loom/s}

Here's a generic CAT diagram of the OEM wiring side to ECM , I found on-line:

(CAT 40 pin ECM generic OEM wiring diagram.png)

CAT 40 pin ECM generic OEM wiring diagram.png (129KB - 342 downloads)

Tried a temporary bypass wire and got a check engine light so I obviously didn't have something right and it scared me off from trying any further. I believe it was the common wire that was the issue.