I recently bought a '00 Bravada. From the day I got it, the AWD Service Light has come on intermittently. It's under warranty, so I took it back to the dealer who said they fixed it. Well, it came on again, I took it back again, and they assured me it was fixed. Well, they fixed it alright - now the light does not come on at all, not even when you turn the key and all the other lights on the instrument cluster come on. How nice...

I pulled the cluster and the bulb is still there. What else should I check? Does anyone know which wire in the cluster wiring harness activates the AWD Service light? What else would disable the light? Is there a sensor somewhere that I should check?

I'm going to take it back to them, but I'd really like to know what they did to disable the light before I hand it back to them. Thank you for any guidance.

Frank

 

Go back to them and ask them to run a Service AWD bulb test. It is something they can control.

I can't remember if the Service AWD lamp is one that normally comes on during the 'christmas tree' bulb test when everything is normal (ie. no pending or stored codes).

 

Thanks for the response. I know the light used to come on when you turned the key. I dont want to take it back to them without knowing what caused the light failure - because I really think they disabled the light instead of fixing the problem which was triggering the light.

 

There is no telling what they did. Did you check the bulb to make sure it still worked? You could try disconnecting the encoder motor on the transfer case and seeing if the light comes on...

 

How would I check the bulb - pull it out and try it in a different position? If so, do those bulbs just pull out?

Where on the transfer case is the encodre motor? Anything special I need to know about removing it?

Thank you again for your guidance.

 

Just disconnect the electrical connection to the encoder motor (next to the front driveshaft).

 

Nice to see I'm not the only one with this problem. I have hadmy 99 Bravada in to 2 different dealers and countless mechanics. No one seems to have any idea why the AWD light keeps coming on, and why changing the fluid in the transfer case seemed to help. There is also a horrible noise that apparentlyonly I can hear, well,me and one mechanic who was honest enough to tell me he had no earthly clue what it was. The tranny is solid, the engine is solid, the AWD is horrid. Any thoughts on the bizzare noise?

 

ann549, as you seem to have a different problem (noise associated), I would suggest that you create a new post on the subject as to not pull this one too far from the OP's actual problem.

One thing that is for sure with the AWD transfer case, you HAVE to use the GM Autotrak II fluid in the transfer case. Any other fluid can and often will cause serious problems with the viscous clutch inside the transfer case.

Also, if the service AWD light is on, then there are stored codes. If your mechanics are not capable of pulling the stored codes, I think it's time to find someone that can. Once you get the codes, post up in a new thread and we'll see what can be done about fixing the actual problem you are experiencing.

I will say this. If someone has substituted the wrong fluid into the transfer case, you are likely looking at a new transfer case ($$$) if you are experiencing binding in the drivetrain. That is indicative of a viscous clutch failure, to which you are better off finding a used AWD transfer case to replace your current one with rather than going through the expense of fixing what is there.