Hey guys, I have a 2001 Dodge Ram 1500 and I have an AC problem. When you turn on the AC it works fine and blows cold, but then when you put your foot on the brake and come to a stop it makes a flapping noiseon the bottom where the open and close door is for hot and cold air and it starts blowing hot air. However if you turn the system off and wait a minute then turn it back on it works fine again and blows cold until you press the brake again, then it goes back to blowing hot. It keeps doing this over and over again. Has anyone had this problem or know how to fix this? Any help is greatly appreciated. Thanks!!!

 

bump

 

Sounds like a vacuum problem to me.
I'd start looking a vac lines on the truck and on a diagram to see where the problem lies

 

It is a faulty blend door or blend door actuator. In either case the dash has to come out to get to it. However, I don't get the braking link unless it's just a enertia or gravity issue that's pulling the door. If that's the case, then the door is loose inside the HVAC box and the air pressure (from the blower) is all thats holding it in position until you brake and it moves forward. If that is what is happening, then the door is faulty as the actuator is pulling it back to the a/c position on restart. And, BTW, the blend door is electrically activated...not a vacuum operated door in this case.
WC