4wd trouble / 97 jimmy 4.3

Since September 2005 the 4wd hasnt been working in my 1997 GMC Jimmy SLE 4.3. When I push 4HI i can hear the TCCM (under radio) click and i can hear the encoder motor still working. I have no idea how to check if the actuator motor is working though. I have already replaced the Vacuum Swith on top of TC because the little tip was stuck in. When I checked for vacuum only one of the three vacuum lines were sucking in air. How many are supposed to be sucking in air to the vacuum switch? Also i took out the battery and tray and i looked and the rubber on the actuator was torn a little. I think it needs to be replaced so i will replace it. ALso when i push any of the 4HI or 4LO buttons the front driveshaft locks in but the front wheels do not lock in. A friend of mine told me it could be the Servo Motor or something that is not letting 4WD kick in. Please help I am very confused. Any help is appreciated. Thank You.

ALso when i push any of the 4HI or 4LO buttons the front driveshaft locks in but the front wheels do not lock in.

Sorry I got no answer here for ya', but I sure got a question...

It seems to me that if, and only if, your front hubs are manually locking, that the front shaft could engage, and the hubs not lock...

If you get any further clues on the problem, I'd like to know - I've got a 4WD misfunction also. See 4x4 default...

Thanks!

i think i found my problem i took out the battery and part of the actuator rubber part was torn. therefore the transfer case was sucking in nothing ut air and the actuator wasn't moving to lock the front wheels. so i am going to replace it ($48.88 advance auto parts) and i will post my result asap.