This happened on my 2000 Jimmy. The canister only has one line coming out. You can see the vacuum line tee off from engine, through firewall and to canister. If you feel below/behind the brake cylinder you can feel the canister nipple. It protrudes into the engine compartment, so you dont have to remove anything, just plug it back in.

I have a 96 i just got about a month ago. First problem: I cant find the other end of the vacuum hose from the front diff actuator. Second problem: only the defrost vents work. i cant find the canaster or the vacuum lines near the brake booster. Any help? i spent the last hour or so searching and no luck!:icon_hyper:

Dont know anything about the front diff actuator 4wd am assuming. I'm sure someone on here can help though. On my vehicle you cant see or even feel for the canister. It is in the fender directly behind the brake master cylinder (on the side of the engine comp, drivers side) If you feel behind/under that brake cylinder you can feel a small nipple protrude from inside the fender to inside the engine compartment) That is the connection for the vacuum canister. Of course you will only feel the nipple if the vacuum hose is disconnected from it. If thats the case the hose has just pulled from it, pretty common from what I understand, and should be dangling somewhere in the back drivers side corner of the engine compartment. Again, this is experience of the same problem with a "different" vehicle. Not sure if above will apply.

Front air vents only
 

I am having a similar problem with air only blowing out the front vents. I get a lot of heat when stopped but as soon as I start moving the temp drops off. When I get to highway speed I need to turn the heat to maximum to getting any warm air at all. Any suggestions on how to fix this problem?