93 S-10 Blzr the 4x4 wont work

Ok here is the deal its a 93 4 door 4x4 S-10 Blazer 4.3L with a manual transfer case shifter. I have a hanes and chilton manual for it and they both are useless in this area. What I do know is the transfer case shifts and engages just fine in 4 Hi and LOW but I do not have vacuume to the accuater under the battery that engages the front differential.I have traced the vacuume lines back untill they disapear behind the bell housing. Where do those lines go? Any Ideas on where I should look next?

There is a three port vacuum switch on top of the transfer case. If it's plugged in, the switch is probably bad (very common). Before you replace it, you might want to check for vacuum to the switch.

There is a three port vacuum switch on top of the transfer case. If it's plugged in, the switch is probably bad (very common). Before you replace it, you might want to check for vacuum to the switch.

Thanks that fixed it perfect!!!!! $38 at local chevy dealer. I dropped the transfer case linkage and had it changed out and working in 30 minutes.