Disconnect the little black hose from the check valve and hook the tester to the hose. If it holds vacuum, turn the controls **** to another setting and pump again. When all the Max, Normal, Vent, etc settings hold. Test cannister then check valve. My check valve tested fine but failed when driving. Run long hose to inside cab to read gauge while driving. Upon gradually loading the engine like going up a long hill at full throttle the vacuum dropped off. I replaced check valve and did it again and vacuum stayed up and cooling continued, heat did not come on. There is also an adjustment for the temperature control **** cable to close the blend door fully so water cutoff valve is not necesssary. It is on the top of the heater core box inside the cab.

 

Hello,
Well, after recommendation of the white vacuum hose (passenger side corner close to firewall), I checked it out and sure enough, it was broke in half. I took the other end with the rubber boot and removed the rubber boot. I cut the tape holding all the wires and hoses in and pulled out the white hose and connected the boot on the good remaining hose and put back to the unit (don't know what that is called). I did this without buying a new hose and going through all the work. Took about 5 min and now my #1 A/C problem seems to be repaired. No more defrost A/C!!! It also seems to have a little more MAX air flow but i would like more. I will take the next suggestion and clean out the fan and see if that helps. Thanks for the help.

 

BEAT YOUR CHEST LIKE A GORILLA!!!!! Arn't success stories fun?