NGA Ram

I have a 99 2500 stick and currnetly have no heat. I checked the coolant, thermostat, and controls.i noticed that when i turn the temp up my blend door doesn't open. So i puilled one of the other vacum lines off and hooked to that actuator and it opened the door and closed it. of course not correct b/c of it being the wrond line. so i am getting no vacume from the correct hose would the problem be in the control unit

Break Away

I had the same problem as you with the same model of truck. The blend door on a 1999 is operated by a electric motor/servo. It is located next to the transmission hump on the passenger side and has a 3-wire pigtail on the side. I removed the motor, plugged the wire back in and tested it by turning the temp control switch....if working correctly, it should turn either way without stopping....it has a circuit board inside to cut it off when the blend door is completely opened or closed. With the motor removed I was able to grip the the blend door shaft and jiggle it with a long set of pliers. It moved after a couple of jiggles....once it "broke free", it was very easy to open and shut with fingers only...I could not determine why or how it got stuck closed in the first place. Re-install the motor and you can ride with heat. Just be cautious "jiggling" the shaft of the door or stressing the motor...it is all plastic. Hope this helps.

By the way, that little motor is a real pain to remove.