my defroster has quit and it's getting cold out. all other modes work fine but no air from the defroster vents. have the rotary style selector. all vac. actuators are working fine.

anyone have similar problems? is it a fan problem. i really don't want to take the whole dash out in order to correct the problem if i don't have to.

i had heard of broken tabs on the door but can't see where the problem would be. any help would be greatly appreciated.

 

There is a vacuum motor directly above the gas pedal that switches airflow to/from the defroster.

Switch the control back and forth from FLOOR to DEFROST (with the enigne running) and see if the motor's actuator extends and retracts. The actuator is attached to a bellcrank arm that moves the actual door that is inside the plenum. Make certain the actuator hasn't popped off the arm. If the actuator is working correctly and the arm is still attached, then the arm has broken off the door inside the plenum.

If the actuator doesn't move, inspect the vacuum lines, test them for vacuum switching.

If a visual inspection doen't reveal the problem, I (or someone else) can look up the vacuum switching logic and the vacuum hose color diagrams.

Steve

 

what year is your truck. I had a 96, and i had a writing pen drop in from one of the defrost vents and jam the vent doors open the im thinking i had no defrost and very little heat. I removed the glove box and cut a hole in the black box that was behind it and found the pen and taped up the hole. (it was a old better truck)

good luck truck
Travis

 

the actuator is working fine i will have to take it out again and look for any thing wrong with the connection inside the plenum. maybe something fell into the defroster and it just wont let the door close.

good opportunity to use the see snake made by ridgid i have been demoing for work.

it is a 2000 f150 4.6 sorry i forgot to put that in the orignal post.

will report what i find. thanks for the help.