Big T
Well-Known Member
Update: Ordered an NP8 Transfer Case Control Module (TCCM) from a salvager in California and had it shipped to Montana. Installed it (several times) and it never even showed any lights on the push button swithches. Put the Dorman reman TCCM back in and it lights solid in 2Hi and flashes in 4Hi, 4Lo and AWD. Returned that TCCM to the salvager for a refund.
Grabbed a NP8 TCCM from a ‘98 K1500 Suburban in a Pick a Part boneyard, installed it and it does the same as the Dorman remanufactured TCCM. I am moving away from the TCCM being the problem. I now think it’s the Transfer Case Range Select Position Sensor. This part is inside the encoder motor. It senses the shift position of the transfer case and sends that signal back to the TCCM and shift buttons. I am clearly getting the truck in 4Hi, but the light still flashing says it’s not getting the return signal of the shift position.
This post on the GMT-400 Forums suggests that the motor in the encoder motor rarely goes out and it’s typical the shift position sensor:
Thread '246GM'
https://www.gmt400.com/threads/246gm.24508/
I saved my OEM encoder motor as it was still shifting into 4Hi. I have see YouTube videos on how to replace this shift position sensor in the encoder motor. I ordered an AC Delco version of the shift position sensor of Amazon for $22 with free shipping and had it sent to Montana. It will be back down later in November.
Grabbed a NP8 TCCM from a ‘98 K1500 Suburban in a Pick a Part boneyard, installed it and it does the same as the Dorman remanufactured TCCM. I am moving away from the TCCM being the problem. I now think it’s the Transfer Case Range Select Position Sensor. This part is inside the encoder motor. It senses the shift position of the transfer case and sends that signal back to the TCCM and shift buttons. I am clearly getting the truck in 4Hi, but the light still flashing says it’s not getting the return signal of the shift position.
This post on the GMT-400 Forums suggests that the motor in the encoder motor rarely goes out and it’s typical the shift position sensor:
Thread '246GM'
https://www.gmt400.com/threads/246gm.24508/
I saved my OEM encoder motor as it was still shifting into 4Hi. I have see YouTube videos on how to replace this shift position sensor in the encoder motor. I ordered an AC Delco version of the shift position sensor of Amazon for $22 with free shipping and had it sent to Montana. It will be back down later in November.