I got a 2004 chevrolet silverado Z71. Its got 81,000 miles and sometimes my service 4wd light commes on while driving on the highway or around town. And it will not let me engage the 4x4 to low, high or auto. If I turn the truck off then turn it back on the 4x4 will work. What could it be. Thanks for the help.

 

sounds like its just a computer glitch. I would make sure all of your fluids are topped off though.

 

i belive its the puch bottom 4x4 piece! mine does the same thing and the switches are know to go out! it just hasnt bothered me enought to buy a new one!

 

Yep, 90% of the time it's the actual switch in the dash...pretty common on the Autotrac trucks.

 

If the switch is going out would it make the service 4wd light come on.

 

had the same thing happen in my truck. Took it into the dealer under warranty and it had something to do with the computer or something in the transfer case. The tech said it had to much play in it from the factory and sometimes thats what causes this to happen with the service 4wd thing to come up. You have to have them re adjust it (pretty sure its done through computer in the transfer case) and make the plates closer together so theres less play. Mine hasn't done it since.

 

Thanks for all the help.