Service 4x4 light

[ryanideus]

I have a 99 GMC Yukon. recently when using 4x4 the "Service 4x4" light will turn on after swiching to 4x4 or auto 4x4. once light turns on you can not swith back to 2wd or any other drive till you turn the truck off, then restart the truck again, then you can switch the drive and the service light is off.

All the drives work fine 4x4, auto 4x4, and 2wd. their is no grinding, funny noises, or any indication that anything is wrong. You just can't switch between them till the truck is turned off and restarted.

My thinking is this is a switch or sending unit somewhere that is bad. does anybody out their have any ideas?

HELP!

 

[ryanideus]

I've done some research and it looks like my problem is the transfer case switch motor. aftermarket part is around $200, has anybody ever changed one of these out? is it something I can do fairly easily?

 

[Bamotte]

Did you ever fix this problem? I am having the same exact problem and wondering how to fix it.

 

[SunlitComet]

have a shop with the right scanner pull the code that is activating your light. there are many causes that would do it. it will point out the issue.

 

[97yuke]

Autozone will hook it up and pull your code for free.

 

[SunlitComet]

Sorry to say but 4x4 codes they will not likely see. It is not part of the OBD2 protocol for OBS. And the scanners I have seen them with is really basic. It ain't no snap or OTC for sure.

 

[brandon1766]

4WD transfer case motor

On my 1999 Yukon when my service 4WD light came on and would not switch out was because of the transfer case motor. As soon as I replaced it I have had no more trouble out of it. it was really fun to change to. LOL had to end up jacking the transmission up to move some plates around.