Transfer case control module

BLCKLBRTRVR

MEMBER
2006 GMC SIERRA
5.3L
V8
4WD
AUTOMATIC
270,000 MILES

System had 12.6 volts. I did a volt drop test on my grounds. The transfer case control module ground to chassis volt drop was 11.8 volts. The C pin black on 4 pin harness(black, red, black and org) on TCCV module was unplugged an had 11.6 volts. C pin on harness had crazy numbers in the hundreds

I had 5.06 volts at switch and on pins on TCC module (5v reference and encoder signal).

On harness (unconnected) at encoder motor I had org 12.6v, tan 11.8v, light green/black 0.0v, black/white 12.6v, brown/white 10.6v, red 12.25, black 10.1v. I am unable to get 5 volt references at this end of harness.

My questions are:

Are grounds out of voltage a issue? Do you think 5 volt reference wire light green/black is open somewhere.
Is module trash?

3 Replies

ASEMASTER6371

MECHANIC
52,797 POSTS

Good morning,

The only reading that is not correct is the ground wire. There should be 0 volts on a ground wire. If you have voltage on the ground, it is not grounded at all.

https://www.2carpros.com/articles/how-to-check-wiring

The rest of the readings are okay except your battery is low. It should show 12.6 volts, not 11.6 volts.

I would repair the ground wire and see if it works. Otherwise, I would replace the module.

In The Left Side Of The I/P Behind The Headlamp Switch

https://www.2carpros.com/articles/how-a-car-electrical-system-works

Roy

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