1986 blazer w-4.3 4x4 not working help please snow on the way

[kwik8]

My 4 wheel drive is not working the indicator light next to my shift unit for the 4 wheel drive lights up when I move it into 4 wheel but the little idiot light that shows a diagram of the axles only indicates that the blazer is in 2 wheel. When in 4 wheel I had someone watch the axle in the front and it is spinning but the 4 wheel is not working. I checked the vacume line quickly and I did not find any burn through but I will check again if that is what someone else thinks the problem is. HElP HELP HELP!!! Big snow coming this weekend and I need my 4 wheel please help!!!!!!!!!!!!

[Fox_Rocks]

ok, first off, the light your talking about isn't a reliable piece of info. but i know what your saying. if the front driveshaft is spinning it just means the the transfer case is succesfully engaged in 4x4, but your front axle isn't engaging....the problem here is normally the vacuum switch on the top of the transfer case (drivers side with 3 vacuum lines going to it) it is approx $55 CDN, the only other thing in the circuit is the actuator located under the battery box, it is what the vacuum switch activates. so what i'm saying is that if you remove the battery box (5 bolts) then shift it into 4x4 you should see this actuator operate....it is almost identical to the actuator used for most cruise control units, just a diaphram (sp?) with a cable attached to it. if you don't see any movement in this unit then i would safely say it's the vacuum switch, but....if there is a rip in the diaphram then it will leak air aswell. if you remove the vacuum line off the actuator and see if it's got vacuum in it, then this will isolate the problem for you. hope that helped, let me know.

[kwik8]

At work now and can´t try and fix problem at the moment but thanks a lot for the help. If I don´t reply any more it is because I got it fixed and am out plowing the mess that is on the way. One way or the other thanks for the help!

[Fox_Rocks]

no prob man.