push button 4x4 light

[99yukon350]

My 99 Yukon (obs) has the push button 4x4 with auto 4x4. I have noticed a couple of times that when it is in 2 wheel drive, the indicator light isnt on. Once I push on it, it lights back up. The other three buttons were not lit up either and I know it was not in 4hi, 4lo, or auto. Should I be concerened?

[c4cruiser]

From what I have read here, the switch assembly does not always last the life of the vehicle. Mine will do the same thing and I will occasionally get a Service 4WD message displayed although there is nothing wrong with the system.

 

When the Service 4WD message is displayed or the indicator lights go out, the 4WD system will not work.

 

I would replace the switch assembly. Costs about $60 and you only have to pop off the dash trim and remove the screws that hold the switch in place. Disconnect the wire harness and reinstall the new switch. You may have to clear any codes that were set and saved in history.

[99yukon350]

I have never had service 4wd light or check engine light, and the indicator light is not always off. I have noticed it only a few times and I look at it regularly now. The last time I caught it was a couple weeks ago. Should I still replace it to be safe? Winter is coming and I don't want to get stuck anywhere.

[c4cruiser]

When the 2WD indicator light goes out on mine, the Auto 4WD does not seem to work when I push that button. Usually, you can feel the AutoTrak system engaging when the button is pushed even on dry pavement.

 

When the light is out, find a dirt road and engage 4WD. You should feel that. Hit the gas to see if the front wheels will spin.

 

I'll bet that with the light out, the 4WD system won't work.