my 4wd light would come on and the dealer found no code, it got to were the light would come on right after starting and it would not always engage in 4wd.After reading this forum and others Irolled the dice and spent the $75 for the switch on the dash. No problems for 2 months now. I have a 99 silverado 5.3

 

they can be a pain..there are 3 things ..

the module needs updated by the dealer

the encoder motor ****

the switch


it can be any or all of those 3

 

Looks like the next one will be the switch. I already had the update and the encoder motor replaced. How come they call it the encoder motor anyways?