4WD "SERVICE" light on...

I have a 2001 Silverado, I drove home in 4wd last night and left the truck in 4x4 all night (the temp is -5) well I get out there today (still -5) and my service 4wd light is on, and my truck is back in 2wd! i went to the dealer and purchased a new switch, well no luck. All the lights are still out, and it still doesn’t work. The fuse is good, and i wiggled the wires around to see if I could get it to work for a min.

Is there any chance something is frozen, or perhaps ice hit a plug and unplugged something on the transfer case?



I went to AutoZone to see if they could erase the code and clear the light. It didn’t work, no code showed up.

Does anyone know how to erase the code?

Does anyone know what to do next?

Thanks for the help

Mike

I have a 2001 Silverado, I drove home in 4wd last night and left the truck in 4x4 all night (the temp is -5) well I get out there today (still -5) and my service 4wd light is on, and my truck is back in 2wd! i went to the dealer and purchased a new switch, well no luck. All the lights are still out, and it still doesn’t work. The fuse is good, and i wiggled the wires around to see if I could get it to work for a min.

Is there any chance something is frozen, or perhaps ice hit a plug and unplugged something on the transfer case?

I went to AutoZone to see if they could erase the code and clear the light. It didn’t work, no code showed up.

I'm having nearly the exact same problem, but I'm stuck in 4wd. I've got a 99 sierra. I buddy with a 99 silverado came over and we tested some parts...

My switch in his truck works, his switch in my truck doesn't work. In my truck both switches will flash all lights real quick when the key goes from off to on, you hear all the normal clicking sounds, but no lights on the switch light up to indicate what driving mode the transfer case is in.

my front differential actuator is stuck in 4 wheel mode... if I take my motor to his truck, and he changes the drive mode from 2hi to 4hi to 4low, my actuator responds just as it should.

If I set my actuator into 2hi mode on his truck, and plug it into my truck, the actuator goes into 4wd mode. I can confirm this with an electric test as listed in my haynes manual.

Its like the truck is stuck in 4 wheel drive mode because that's what it is being told to do.

I'm thinking that my transfer control module is wacked, and is what is causing my problems.

i have to check out the 4-wheel drive light, my buttons are on the dash, 2000 silverado. do you take off the panel where the buttons are, thanks

i have to check out the 4-wheel drive light, my buttons are on the dash, 2000 silverado. do you take off the panel where the buttons are, thanks

this is another vehicle owners posting ,,,you should start a new posting of your own,,,with your problem/description..

I have a 2001 Silverado, I drove home in 4wd last night and left the truck in 4x4 all night (the temp is -5) well I get out there today (still -5) and my service 4wd light is on, and my truck is back in 2wd! i went to the dealer and purchased a new switch, well no luck. All the lights are still out, and it still doesn’t work. The fuse is good, and i wiggled the wires around to see if I could get it to work for a min.
Mike

I do not think it'll work, but disconnect battery cables, both of them, and leave it so overnight.
I am also assuming that you installed the new switch, right?
My service 4WD light was fixed in a heartbeat with a new switch installed.