Well .... I have tried everything suggested here to fix my air but still no luck. I replaced the GEM module, checked blend door motors, ran all vacuum lines and find no leaks. I removed the inner fender and checked the vacuum canister it has good vacuum.I replaced the heater control unit. I am stuck. It still blows through the defrost. Again, if I remove the hose and draw vacuum from the little black vacuum thingy behind the glove box by the kick panel it blows through the dash. I shut it off then it defaults back to the defrost. HELP ME It's hot. Thanks all.....Paul

 

what year?

 

Sorry. It is a 2000 3.0 Flex 4x4. Any help is appreciated.

 

At the mode selector, check vacuum lines 2,5,6. Line 6 controls the panel/ defrost door. and lines 2 and 5 control floor/panel door. You very well may have a broken mode door or defrost door.

 

1998~2000.5 4x4 Rangers used the infamous Pulse Vacuum Hublock system to engage the front hubs when in 4x4 mode. The PVH system is a notorious leaker and it shares vacuum from the the vac reservoir with the A/C system.

4x4 Rangers in the first part of the 2000 model year had PVH's but those made later in the model year did not. If yours falls into the first group, then it has a branch vacuum line teed off from the A/C vacuum line to the PVH solenoid and you might try disconnecting and plugging it temporarily to see if that fixes the A/C control problem.