First time on the forum, but I’ve been using this blazer nation for help and guidance for over a decade now. I’m calling on you all once again lol. I have a 2005 ZR2 blazer, and currently my 4x4 does not engage the front tires. When I click the 4Hi button, or even the 4 Lo, the light goes solid as if it was engaged, but it wasn’t until we got hit with blizzard conditions and I was sliding all over the road that I realized it did not work. After scouring the internet, I checked all the vacuum lines and found a major hole in my line coming off the engine block. So that was replaced and now working. I used a vacuum line tester on all other lines leading into the actuator and they appear to be ok, then I tested the actuator itself for vacuum and that too worked. Next, I swapped out the actuator cable because my old one was seized. After installing I was able to hook up the battery without the tray, start the truck, and engage the 4Hi and see that the actuator is in fact compressing and the cable is working. But, still no spin from the front tires. I’m at a bit of a loss. Next up is attempting to change the transfer case motor, which I believe is an NV236 for the 4 button cluster with the Auto 4x4? I purchased an NV233, but wasn’t sure that would work with the auto 4x4. Am I on the right path here? If anyone else has any hints or tips, would be greatly appreciated. Thanks guys

 

NV236 is the transfer case you have if you have 4 buttons on the dash with one being a big circle that says AUTO 4X4, an NV233 will not work with that truck without major wiring and computer alterations, can you verify that the transfer case is spinning the front prop shaft with all 4 wheels off the ground and the truck stood up on jack-stands in Manual 4HI/4Lo?

 

I didn’t get the chance to lift it off the ground (lack of that many jack stands to spin all wheels), but a new problem arose after I swapped out the transfer case encoder motor. Initially all lights worked fine, but now upon starting it a second time all my 4x4 cluster lights are out, and my service 4x4 light came on in my dash. I’m running out of ideas. May have to just bite the bullet and drop it off at a shop. Unless anyone has a Hail Mary of an idea.

 

Scratch that, the service light turned out to be for a blown ATC fuse. If anyone has a Service 4x4 light in their truck and their 4x4 cluster lights go out, definitely check that. Didn’t know that was a thing until I found a thread where someone said they had to do that for their Silverado. Going to borrow some jack stands and get it up off all fours and see how it goes from there.