Ok ok when that hose was not plugged my heat dash controls were not operable. Now they are... I'm hoping this is the problem and finally solves my 4x4 issue. I'll keep everyone updated

 

If you use the instructions I put at the very end of the thread I provided before, it is about a 15 min job. Be careful when you "nudge" the ABS out of the way. The nipple is just inside the fender and if I remember correctly there is about a 1 inch hole it the fender to access it. You'll definitely need a mechanics mirror to see the nipple (unless you want to do some weird headstand in your engine compartment). But you can feel it with your finger.

 

Based on what you know....Do u think that is the reason the 4x4 is not engaging? That is the ultimate question lol

 

If I remember correctly, my 4WD would engage even before I found the disconnected line. But it was slow. When I repaired the line I got instant engagement. I know you've stated that you replaced the actuator, but have you actually taken the battery tray out to watch the actuator when the vehicle is running? Of course you would need to have the battery connected remotely (I used jumper cables with the battery on the ground). With the battery tray removed and the truck running, have someone engage and disengage the 4HI so you can watch the actuator pull the cable. If it isn't doing it in 4HI, but it is in 4LO...I would suspect something more in the electronic arena.

 

BTW..have you gone through this thread yet? https://blazerforum.com/forum/tech-a...ill-help-7180/ It really helps understand the whole system. According to post #5 in the thread...your symptoms may indicate an "Encoder Failure".

 

The vacuum leak is cause for the front differential to remain disengaged regardless of the 4wd selection being 4hi or 4low.

There are other parts that can cause this same effect, however, I think you have replaced or checked a majority of them.

However, if 4lo works and 4hi does not I would venture down the encoder motor road. Have you had a chance test and see if the differential engages in either 4hi or 4low?

 

No I have not... I'll dig more into It tomorrow and keep you guys updated

 

No I have not.. Would the actuator still engage if encoder motor is not working? .

 

No. When the transfer case switches to 4HI (the encoder actually does the shifting), the vacuum switch closes and sends the vacuum to the actuator. If the encoder is not shifting the transfer case into 4HI, then the vacuum switch will not close and will not send the vacuum to the actuator.

 

Ok do the vacuum switch is inside the encoder motor... I am hoping that this is where my problem lies