VEHICLE ALREADY FIXED, INFO ONLY.

Vehicle came in for dash goes out, windows don't work, intermittent. Turns off truck, then everything works for a while. Customer already installed BCM and provided PCM that he wanted us to program. After extended testing and research (alternator and PCM failures mostly) recommended OEM alternator, not available. Found several questionable grounds (repaired) Replaced alternator and all was good. 3 weeks later customer called and reported it was acting up again.

Double checked alternator control wires, OK. Found when charging voltage went above 13.6 VDC the dash went blank except warning lights. Using the PCI network connector, above steering column, isolated to pin 2, goes to several modules including BCM, SKIM, ABS, DDM and others.

Found Drivers Door Module contaminating network signal only when system voltage exceeded 13.6 VDC. OEM not available, second aftermarket finally worked.

Trust your tools. HTH

Jeff Wade
Manager/Technician
Elm Street Garage LLC
Mountain View, Missouri, USA