Chevrolet Repair: s10 4x4 not working, s10 blazer 4x4, s10 blazer

Question
I have a 96 S10 Blazer 4x4 In which the 4x4 is not working. I checked to see if the transfer case was engaging by turning the front driveshaft which turned freely in 2wheel. I then selected 4H and I heard the actuator activate. I then checked the front driveshaft and found it was engaged, it would not turn. I did this with only the front tires off the ground. The front wheels turned freely also. Is there an actuator on the front transaxle that is not activating? I counldn't locate any controls connected to the front transaxle. I'm not sure how the front wheels engage. The fuse for 4x4 is ok. I located some relays in the glove compartment but are not sure what they are for. Thanks for your advice.

Answer
Hi Ed.... there is an actuator on the front axel...cable pot should be under the battery box...check that you have vacum to it...if none follow vacum line to solonoid and check to see if you have vacum there...if you do check to see that the solonoid is working...if not replace it....hope this helps