My a/c will only blow out of the defrost vents. After driving a while it will barely blow out of the regular vents. I'm sure its just a loose vacum line. Where is the a/c vacum pump?

 

a/c vacuum pump - aka. the engine.

 

Then where is the vacum line?

 

What are you driving???

 

97 jimmy 4x4

 

The vacuum line runs from the intake to a 'T' where it splits down to the vacuum switch on the transfer case on one side and into the firewall on the other. It may go through another 'T' before going through the firewall in which case one side of the 'T' would go into the firewall and the other side would go to the vacuum reservoir. The vacuum reservoir should be located inside the driver side fender.

Once on the other side of the firewall, it runs into the vacuum harness on the back of the HVAC module in the case of the manual HVAC system or into the vacuum control module in the case of the automatic HVAC system.