Datalink Issue

Good file.

 

Thanks I have some electrical experience with the cars but not trucks. I would use wiring diagram Snail express send and will try to pinpoint where the problem coming from.

 

Regarding QualComm, did you just cut wires to antenna or you did disconnect it from the truck circuits. If quallcom still connected to the truck it has bidirectional amplifier which is going bad sometime. Looks like piece of pipe on QC cable.
Open the dash and disconnect every single wire from the truck.

 

I told you where to look first.

 

Just to confirm, you said to look in passenger area/kick panel for J1939 qualcomm wiring?

 

On a 2006 VNL that's where the wiring from the qualcomm came. From the back of the cab to under the dash or up to the blower area, I think, under the passenger floormat. The easiest way to solve the datalink problem caused by a shorted qualcomm cable that was cut at the back of the cab is to just separate those wires on the back of the cab and heatshrink them so they'll never contact anything.