i have replaced the vacuum switch on t case the cable was slightly froozen and i broke it lose and the thing that pulls the cable works fine. the front drive shaft spins but wont engage if you manually pull the cable in makes a slight click but not engaged

the car use to always try to be engaging the 4wd because the vacuum switch ball was stuck up but even with the vacuum thing always pulling the cable it wasnt in 4wd

this is a 1997 blazer 2 door 5 speed

 

If the transfer case does not engage the front driveshaft, there could be a problem with the TCCM or encoder motor. Engine at idle, trans in neutral, 4WD selected: The vacuum line at the axle actuator under the battery must have manifold vacuum. If it does, make sure the cable pulls in about 1/2" to 3/4". If the cable pulls in, the right front wheel should lock in. If not, the clutch mechanism in the axle tube needs attention.