Transfer case not shifting into 4x4

[Halfton_z71]

Hey guys, I'am having trouble shifting into 4x4. When I first bought the truck there was a service 4wd light for about 2 days then it disappeared. The previous owner said they replaced the switch (it is the push button 4x4) and 4 hi, 4lo, and auto 4x4 worked. But when I bought the truck it was not working, so im not really sure how credible the seller was. When I press the buttons there is no sound like the transfer case actuator is trying to shift. Also there is no orange light on the buttons themselves indicating what mode your in. I've checked grounds and fuses and everything looks fine. Im wondering if it is the transfer case control module that is bad or something on/in the transfer case itself. What should I check for next? Any pointers would be great! Truck is a 99 1500

 

[stutaeng]

Is that the NP246 (has the round button on top) Autotrak?

I had a similar issue on my 04 Suburban and it was the reluctor wheel on the encoder motor. It was like $20 part shipped from Rockauto.

 

[Halfton_z71]

Is that the NP246 (has the round button on top) Autotrak?

I had a similar issue on my 04 Suburban and it was the reluctor wheel on the encoder motor. It was like $20 part shipped from Rockauto.

Yep, its the NP246. I'll have to look into that.

 

[stutaeng]

Check out post #8 & #11 here: performancetrucks.net/forums/tuning-diagnostics-electronics-wiring-161/service-4wd-message-560255/

You can take it apart and measure the resistance of that wheel. Mine was very erratic as I was spinning, jumping all over the place. Alldata has instructions on how to clock or time the wheel, but I believe you just align the wheel dot with the case mark.

I hope this helps.