I have had it diagonosed and it is reading code co3021. lOCK CIRCUIT MALFUNCTION.I would like to know what that means.
I have 2005 silverado it is stuck in 4wd.and service 4wd light is on. on 2005 Chevrolet Silverado 1500
poss your lock solenoid is stuck and not working.its on the side of your transfer case. also you could just have a bad set of switches. ck for pwr at the solenoid then test solenoid if you have pwr to it. cycle the switch off and on to see if the switch is working