4x4 not engaging

[02duramax]

Hello,

 

It recently snowed so I pushed the 4x4 hi button on the truck for the first time and the front tires didn't engage. Nothing different happened then 2wd. Where do I start checking for the problem? Is there still an actuator on the front axle? What is a good service manual for this truck? Everything I see doesn't cover the diesel.

 

Thanks

 

2002 silverado 2500HD

[HighSierraZ-71]

I pushed the 4x4 hi button on the truck for the first time and the front tires didn't engage.

 

 

My new 06 Sierra Z-71 did the same thing with 528 miles on it. After replacing the encoder motor, the problem found by the dealer were loose connections at the fuse block. I would check that first, then go to the expensive things like a new switch, encoder motor, resetting computer, etc.

[02duramax]

the problem found by the dealer were loose connections at the fuse block.

 

 

Did the lights on your switch still work?

[GM-Tech]

Do the lights that indicate position work on your switch? There are a number of software upgrades for that system so it may be as simple as that. Also some problems with the encoder motor sensor, but without some diagnosis and seeing if there are any codes, it's hard to say what's wrong.

 

As for a manual... Helm, Inc. sells the service manuals that the dealers use... if we used paper manuals anymore. There always used to be a diesel supplement manual, but as I said, we don't use paper manuals anymore so I'm not sure if that's still the case.

 

The URL for Helm is http://www.helminc.com - I just looked and there IS a separate diesel supplement and it's only 10 bucks. The regular, full manual set is $135.00. Well worth the price if you're going to do more than just maintenance on the truck.

[02duramax]

Do the lights that indicate position work on your switch?

 

Yes, the lights still work on the buttons. I have seen the 4x4 service indicator flash briefly, but not stay on. It just flashed on the other day when I started the truck for about 1 second.

 

Would a standard OBDII code reader work for pulling out the codes? I've been looking for a reason to buy one :-)

 

Thanks

[GM-Tech]

Would a standard OBDII code reader work for pulling out the codes? I've been looking for a reason to buy one :-)

 

Probably not, but I don't know what's out there. From what I know most only read engine related codes. But go buy yourself one for Christmas anyway. Tell your wife that GM-Tech says you need one.

[HighSierraZ-71]

Did the lights on your switch still work?

 

The lights on my switch were lit, but when you pushed the 4x4 buttons they would only flash and the four wheel drive system would not engage. It was an intermittent problem at first, then would not engage at all at the dealership.

 

The dealership reprogrammed the switch per GMs recommendations, this worked until I got it home after the first visit to the service dept. The second trip resulted in an overnight stay for my truck, but the dealer was nice enough to give me a free loaner car since I live 30 miles away. After replacing the encoder motor and tightening the terminals it was fixed.