Those hand held jobbies work well. Takes quite a few pumps to achieve 20" of vacuum though. Just watch the gauge and when it reaches 20", you're done. If it leaks back to zero, or doesn't achieve 20", you've got a leak. Thats where the chart comes in handy. The left column indicates the mode. As you go across to the right, it tells which ports, (on the mode switch) should have vacuum, or are venting. Figure out what mode has a leak, and trace that color vacuum line to the actuator. For example: If it leaks vacuum in the defrost position, only ports 1 and 6 should have vacuum, (6 should have vacuum all the time when the engine is running). The leak is either the brown vacuum line, (#11) or the actuator, (#15).

EDIT: If you connect the vacuum pump directly to the hard plastic line under the hood, you will only be checking the HVAC system.

 

ok, so just pulled a test run and found at the firewall line 0 vacuum. Do the lines all go in with the wiring harness?

When it is in the cab does it do behind the dash gauge cluster? I am going to take it all apiece part by part, to find this pain.

Can i start with the contol unit out and pull vacuum back words, like to the selector ****?

 

Zero vacuum on the black hard line under the hood? If that's correct, the problem is not in the cab.

 

Yes that hard black line going in to the cab about 6 inches long and is in with the wire harness

 

1. Under the hood there is a rubber vacuum line that connects to the hard plastic line, unplug the rubber line from the plastic line. Connect the vacuum pump to the plastic line and apply 20" of vacuum. It should hold indefinitely. Post the results.

2. Disconnect the vacuum pump from the plastic line, and connect the vacuum pump to the rubber line. Apply 20" of vacuum to the rubber line. It should also hold vacuum indefinitely. Post the results.

The results will tell if the leak is under the hood, or in the cab.