Hello again, I don't remember the last time I was in this forum but it must have been a few years ago when I had my s10.

Anyways, I'm back with a 98 blazer zr2 and i'm hoping you guys can be as helpful as before.

My problem is this...Just bought the blazer yesterday with the 4x4 not working. The push button switch kinda works, I believe it needs to be replaced but I can wiggle it enough to get a steady 2wd light on. When I press 4hi, the tccm clicks a few times then the light on the selector switch goes back to 2wd.

So far I'm at the 4x4 actuator under the battery tray and while there is a vac hose connected, I have absolutely no vacuum to speak of. The diaphragm isn't in the greatest shape either but I don't see any tears and if I manually push in the diaphragm, the cable feels like it is attached on the other end.

I removed the vacuum line at the transfer case and I do get vacuum there, along with a bit of trans fluid leaking out.

That's where I'm at so far. 4lo also isn't working. And i'm only getting air out of my vents on the hvac, no floor.

Where does the vac hose at the 4x4 actuator go to and why wouldn't I get any vac?

thanks

 

The vaccuum line from that actuator goes directly to the vaccuum switch. Sounds like your switch is bad. Also if the switch is bad and letting fluid into the lines, your lines might almost be gone from degrading. If the diaphram is bad then this also doesn't help your cause any. I would replace the switch and look into changeing the vacuum lines also. Your switch is blinking because the transfer case is engaging (probably) but the front differential isn't locking in because there is no vaccuum pulling the gears into mesh. And there is a sensor in the front diff carrier that tells the trucks computer that it is in 4x4. That is why it blinks.

 

Thanks, I do have vac at the switch, not sure which line it is coming from but I am getting suction on my thumb. It did feel like only one of the three lines that are at that end. Should they all have vacuum?

I forgot to mention that I recently totalled my last blazer 4x4 only on the left front side though, so I have lots of parts available. I had replaced that switch on the last one thinking it was causing a leak I had. Ended up being from the tc vent. I pulled the filler on the tc and it gushed about two quarts of fluid out, obviously leaking from the tranny over. I'll swap them over and see if it works. Hell, i'll probably swap the actuator and encoder motor too.