94 blazer vortech bush putton 4x4.

4x4 don't work but the 4hi light stays on all the time.
There is an open vacuum line near the transfer case.
I can't find any diagrams that have the transfer case vacuum line routes! when I click on the transfer case link at autozone it goes to a mercury sable !!!

I see there are three vacuum lines that go to the transfer case with one that splits into 2 with a y connector, the longer one off the y is the one that is open. Otherwise all 3 go to the junction that connects to the nipple on the transfer case. I pulled off the junction accidentally because it was so loose and it looked like there was ONLY ONE nipple, which didn't seem right seeing as how there are three lines!
I can't find any obvious spot for the vacuum line or is it supposed to be open? I noticed an open line with a check valve in the engine bay.

Thanks in advance

 

bump.

 

Sounds like your vacuum switch at the T-case has two nipples broke off. Actually the system is pretty simple. You have vacuum that comes from the engine to the switch. When you engage 4 wheel drive it opens the valve in the switch and ports vacuum up another line to your front drive actuator on your fender. The third is a vent line for the T-case and is routed up on your firewall and is supposed to be open (you have a little vent fitting on the end). These vents are all over the truck. For instance even your rear differential has one. They pretty much all look the same.

 

Check out the diagrams in the thread below:
4wd Front Axle Clicking When in 2HI - Goes Away when in 4HI/4LO
Don't let the title deter you from looking inside.

 

omg thanks Im so happy I have had only 2 wheels for a year.

 

Should have asked sooner I guess. Good luck man.

 

I only drive it when my neon is getting upgrades.

 

Great info... Swart! Just what I suspected just didn't know how the NV233 Switch worked. Looked to simple of a device to malfunction. My '95 Jimmy had constant vacuum at the actuator in 2WD. Quick $20 fix.