The 4wd was not working. Someone said try the actuator, Ichecked the old one and it was in good condition and held vacum. I started the car to put it in 4wd but the actuator did not move and thetrasfer case sounds like it is engaging.
After reading another post today sounds like it could be the vacum switch? There are three hoses that go into a plug that screws into the top of transfer case, is this it?
Does anyone know the actual name of this vacum switch and is it a dealer supplied item only? The guy at the auto supply store couldn't find it.
Thanks

 

The vacuum switch is named just that. It should be available just about anywhere (napa, advanced auto, autozone, etc).

You may want to check over your vacuum lines to make sure that there is not a leak in either the supply line to the switch or between the switch and the actuator before replacing the switch.

 

OK, I fixed it!
With all the great posts on this site most posts lead to vacum problems. I started tracing hoses and found a hose on the driver's side that connected a hose from the manifold, then another hose that looked like it ran to the transmission, then a hard hose going through the dash, then THERE WAS ONE OPEN END. It looked from the shape (bulge at end)of the hose that it had been connected to somewhere but after some time I could not find where it connected.
So for a quick test I used electric tape to plug the vacum leak! IT WORKED!
4wd is now working.
HOWEVER, anyone have any ideas where this should connect? I is around the ABS system drivers side?
Thanks, these posts are a lifesaver, and easy on the wallet!!!

 

Underneath the ABS computer there is vacuum tank in the drivers side fender. This is where the mystery hose goes. Look for posts in General Tech/2nd Gen. There was a post (most recent on 12/29/08) about no heat with great photos that will show the vacuum lines.