Help: 05 GMC tccm

PureHybrid

Isuzu Shakes IT
Feb 15, 2012
3,322
359
83
Central OH
Having trouble getting my truck in/out of 4wd after the conversion using Ben's harness. I emailed him and he gave me a couple things to check, and replied but you know how that goes.

Basically I'm looking for a known good TCCM, gm part# 12590219 to rule this out as the issue.

I have a buddy that worked for GM for 20+ yrs and he got me a couple diagrams of a 4wd truck, and power reference signals as well as resistance at the switch has turned out good. My v2 scanner will not communicate or recognize that the tccm is present in the truck, but I'm not sure if it should based on how Ben set this harness up. None of the indicator lights are lit up, only the backlighting is on the push button panel.

If anyone in Zanesville or central OH has one that I can try, let me know.
 

PureHybrid

Isuzu Shakes IT
Feb 15, 2012
3,322
359
83
Central OH
It's not one of his boxes, he made a 4wd conversion harness for me. I was told it's basically a standalone setup, shouldn't mess with the ecm I assume