I have the service 4wd light showing on my truck. I replaced the transfer case switch on the dash with no luck in removing the service 4wd warning. I disconnected the negative terminal on the battery to hopefully clear the warning and reset the system to acknowledge the new switch if that was the problem. Now when I reconnected the battery, the automatic climate control system comes on set to 74 degrees and only blowing from the defrost vents. Turning the truck off and on does not reset the system. It will only blow from the defrost vents even if the other vent buttons are pressed. Any ideas on how to reset this system or did I make a mistake in disconnecting the battery?

Check the electric actuator above the gas pedal- see if it is still connected- I've seen a few C/K trucks where the rod come loose because of the poorly designed clip- and it does as you describe- all air goes to defrost...

I have the service 4wd light showing on my truck. I replaced the transfer case switch on the dash with no luck in removing the service 4wd warning. I disconnected the negative terminal on the battery to hopefully clear the warning and reset the system to acknowledge the new switch if that was the problem. Now when I reconnected the battery, the automatic climate control system comes on set to 74 degrees and only blowing from the defrost vents. Turning the truck off and on does not reset the system. It will only blow from the defrost vents even if the other vent buttons are pressed. Any ideas on how to reset this system or did I make a mistake in disconnecting the battery?


what is the year and model ?

2005 Silverado 1500 Z-71 with automatic climate control ac

for the 4wd light.... i have heard it can be the vehicle ground strap. i had it come on in my 2003 and 2005, i never did anything to it. the light went out by itself. and i would occasionally put it in 4wd, just to test it. good luck!

2005 Silverado 1500 Z-71 with automatic climate control ac


on the ac i believe this automatic control needs to be reset...i will check for that proceedure to clear the lock up of ac control...look in your owners manual for any troubleshooting aid in this ...


on the transfer case 4x4 service light you will need to get failure code dtc and report the results,,,,if the vehicle has 4x4 operation and this light is on it may be electrical signal/current flow/voltage of an improper value.. need dtc to find defective part..