Recently bought a used 2003 Tahoe - 4x4 worked intermittantly. Bought on the cheap. Seller had quote from dealer to fix 4x4 for around 1100(reflash tccm and replace encoder). Service 4wd message was always on the dash. Dealer said code was C03-27 i believe. Truck was always stuck in 2wd high. Lights worked on the switch - nothing happened. Everyonce in a while you could shift it into 4x4 hight or auto modes. I would usually take a couple tries to then switch back to 2wd.
I had local dealer reflash the tccm but couldnt afford the remaining 900 for the new motor and labor. I purchased the new motor and installed it myself.
Still in 2wd high and nothing happens when you hit the buttons. I have read all the forumns about the switches being bad - so I switched it out with another good one from a friends truck. No change. My switch worked in his truck.
What else is there to look for? Tccm is good. New encoder motor, good switch. I cleaned up the grounds under the drivers door and inspected as much wiring as I could find for breaks.
Any ideas where to go next?
I had local dealer reflash the tccm but couldnt afford the remaining 900 for the new motor and labor. I purchased the new motor and installed it myself.
Still in 2wd high and nothing happens when you hit the buttons. I have read all the forumns about the switches being bad - so I switched it out with another good one from a friends truck. No change. My switch worked in his truck.
What else is there to look for? Tccm is good. New encoder motor, good switch. I cleaned up the grounds under the drivers door and inspected as much wiring as I could find for breaks.
Any ideas where to go next?
