ive got a 03 z71. the service 4wd light has came on twice. turn the truck off and wait, turn it back on and all is good. well last night i was sitting in a drive through and started to run the 4wd through the gears. well at first it wouldnt switch into 4hi or low. the light would jst sit there and blink. so i pushed the 2wd button and it stopped blinking. so after a min i pushed it again and after a min or so of blinking it went into 4lo. well when i tried to put it back into 2wd it wouldnt go. so i decided to take it easy home in 4lo. after bout 5 min i pulled over put it in neutral push 2wd button and bout 15-30 later it went back into 2wd. do yall think its my switch or is the encoder motor goin out?

 

mine is doing about the same thing. did some research and seems to be the switch. checked with a buddy who owns his own shop and he agrees. just waiting for my switch to arrive and swap em out to confirm. seems that the switch is sending bad signals.

 

let me know if it fixes ur problem. thanks

 

swapped out switches. switch stays lit up in 2wd as it should, but service still comes on, i think i may have a bad ground issue.

 

both of you need to pdate your programming, if available.... and replace the sensor inside your encoder motor...

 

I assume you can just go to the dealer and do the update?

 

ya my mom 03 chevy did the same thing, it had to do with the programer for the 4wd or something, it wasnt expansive to change tho,it would not move out of 2wd

 

What does Pdate mean??? new to the site sorry dont know the lingo

 

It was a typo.

Update

 

99-02 switch only. 03 and up, dealer to reflash and encoder motor sensor. Typically....