Ok 4x4 not working tc kick in spins driveshaft but no turn in the tires, light doesnt come on etc.. I seem to have vacum and the vsv are working (i think) , Question is when i put it in 4x4 i can hear a click under the dash like a relay or something, so i found the circuit opening relay unplugged it and without it in it dont make the click, does the 4x4 run through this relay and why does the truck run still if this relay isnt in it does controll the fuel pump correct?? Any help would be great I'm beginning to freak out...
-Dustin

 

Any help would be great

 

What type of hubs do you have? Manual or auto diff disconnect? Are your axles at least turning?

 

Its ADD

 

I had to have the electronic engagement unit replaced on mine when I bought it in 2000 w/92,000 miles on the clock. First suspect vacuum problems, but confirm that.