Service 4WD light. need help.

**Tiny1987** · 02-08-2009, 04:55 PM

ok 2004 silverado 1500 4x4 5.3L crew cab. just the other day the service 4WD display comes up on the readout. then next ignition cycle it goes of. i thought sweet problem solved

. i was wrong. 2 days later comes back on stays on for several ignition cycles then randomly decides to go out. checked for history codes this time and found a c0374-generic malfunction. went through repair manual and found all to be good. of course the light was off at this time. i've read in a couple places that it could be the encoder motor or it could be the 4WD switch in the dash. hoping to get some help thanx.

**Springthing** · 02-08-2009, 07:42 PM

I think you hit the nail on the head with both of those.

Either the switch in the dask or the transfer case actuator.

I'd suggest a (trusted) salvage yard switch module and then.... well, someone else will have to tell you how to check whether the actuator is good or not.

Good luck,

**ahm1127** · 02-10-2009, 01:47 PM

I am having same problem with my 05 suburban, dealership says they replaced switch (didnt tell me what switch) but problem continued.
Back 2nd time & couldnt switch between 2 & 4 wheel (no lights). Had to reprogram computer, problem continues with SERVICE 4x4 but i am able to use 4x4.
Going back for 3rd time only because its under warranty. I will try to get some more info when i go back for 3rd time.

**whatever** · 02-10-2009, 01:56 PM

Yep. You are looking in the right direction. I had a 04 Trailblazer that I replaced the switch in {that did not work} then I replaced the actuator and had to have the PCM programed to recognise the new part and that fixed it. Good luck.

Mark.