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2015 GMC Sierra NQH transfer case stuck in neutral.

Detroit Diesel


Hello, about 7 months ago I smoked my 6l80 transmission, removed it with the transfer case still attached last fall, before removing it I made the mistake of putting the transfer case (RPO code NQH) into neutral to aid with removing the rear driveshaft. Fast forward to about a month ago I finally had time to reinstall a new (rebuilt) transmission, upon reinstalling everything I noticed that my transfer case shift knob was not responsive and had no lights (other than on startup when it does a function check or whatever) I got a few wiring diagrams and checked over the whole system, replaced the transfer case actuator motor and the knob on the dash, still cannot get the POS to respond and do something. At a loss with this truck and contemplating scrapping it, it's had 4 motors, and 1 transmission in 126k miles, let alone over 30k in parts and labor. 


I recently got laid off and buying a fancy scan tool and/or having it sent to a shop is *NOT AN OPTION*.


I desperately need advice and or assistance as to WTF I should do with this POS that has been nothing but problematic since day one.


below I have sent all the PDF pages I have used to trace and track wiring schematics.

front axle controlls.webp

front axle actuator.webp

Power, ground and shift controls schematic.webp

T case control switch X1.webp

T case encoder motor.webp

T case shift control module X2.webp

T case shift control module X2.webp

T case shift control module X3.webp

T case shift control module X3.webp

T case shift control module.webp

Transfer case control schematic.webp

Power, ground and shift controls schematic.webp

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