Hey guys, been awhile since I've been on here, getting a little fed up with the ZR2...
So my vents started acting funny a few months ago, not wanting to switch between floor, vents, defrost etc. There was a slight hissing that progressively got worse coming from what sounded like behind the ash tray, then the flapper doors stopped working all together and it just blows out of the floor. A little while after that I went 4 wheeling and noticed my 4x4 wasn't working so I took my battery and battery tray out to check my vac boot that locks the 4x4, I ran the battery off cables and watched the boot as i engaged and disengaged 4x4, it moved, but not enough; you could squeeze the boot with your hand and it would engage. So I did some research and found out that there is a vacuum switch on the transfer case that can fail and fill your vac system with transmission fluid, which i'm pretty sure is what has happened to me... I replaced it, everythings still the same. I'm sure someone has dealt with this before...HELP! What do I need to do?

 

Fix the leak behind your ashtray

 

Find the vac leak and fix it

 

Though you changed the switch, there is probably still fluid in your lines, vacuum actuator, reserve canister, etc. Without cleaning all of the fluid out, you'll still have the problem. Check out the below link, be sure to click the link at the bottom of the first link also where it states "Continue reading". If you got the Dorman switch, even though it's new, you may want to pull it and look at it. It fails. Learned that from experience. You can tell if the little ball is not where it is supposed to be and is sucked halfway up in the switch. Somewhere on here someone has a link to a better switch.

GMC Sonoma & Chevy S-10 Transfer Case Vacuum Switch

 

Wow, that looks like a major pain. I really hope mine aren't filled with fluid. When I looked behind the glove box at a few lines they seemed to have a slight "greasy" look to them but no actual fluid came out of them, what do you guys think, would fluid pour out if it was to that point??? really need to get in there and see what's what. What an utterly STUPID design...thanks GM!!!