Where is the 4x4 switch on a 89 S10 blazer the front axle wont engage in 4x4?

there is a vacum actuator located on the passenger side of the vehicle.checck the vacum hose to make sure it is getting vacum when you enguage the switch or gear shifter.this has a cable that goes to the front difererential that acuates to engage the front diferential.the vacume hose may come loose.or the cable pulled out of the holder that connects to the acuator.

My 93 blazer has a vacum line behind the intake in front of the dis. it fell apart 4X4 stopped working i just replaced it it worked great 1993 4.3W