Chevrolet Repair: 4x4 engagement, battery box, solenoid

Question
I have a 91 S10 and i cannot figure out why the 4 wheel drive will not engage. I don't even know where to start looking. Can somebody help me. I have heard something about vacuum but am not sure if its the lines or the solenoid or where the solenoid is located.

Answer
Hi Brian... check the vacum line to the actuator pot under the hood... it should be in right front corner and may be under the battery box... if the line has no vacum on it check the solonid that opens the vacum. it will be in that line as well...follow line to the engine and make sure that there is vacum. check line for cracks and leaks...hope this helps