2002 2500 hd push button 4wd

[454ss]

my truck went into 4 low by itself and is stuck there, I took the switch out and tried it in another truck and it lights up and works. I replaced the transfer case control module and no change, the lights on the switch don't come on and it wont do anything. the 15 amp 4wd fuse in the dash is good. could it be the motor on the t-case? that's all that's left but wouldn't the switch still light up? the 4wd rpo is np1. please help!

[ShawnR]

Most likely the encoder ring in the transfer case shift motor. Less likely but possible, corroded wiring to the shift motor. Just a heads up, sometimes the truck needs flashed when you install a new ring or motor, sometimes not. Follow the button/ignition sequence and plug a new motor in before removing the old one to see if you have to flash.

[454ss]

thanks, what is the button/ignition sequence?