on my o3 the heater controll will work in every position except defrost,I can change it to the floor and vent and it works fine but no matter what setting i have it in no air comes out the defrost vents need help its cold here!!

 

A common problem. Your recirculation door is probably broke. It requires removing pretty much the whole dash to fix it. Last I heard there was a nationwide backorder on them.....

Good Luck.....

 

great,thats not what i wanted to hear

 

Mine just went out to

 

what i dont uderstand is that it switches to everything else on the controll,floor and the vent,so why doesnt it switch to derost?

 

Mode door isn't moving to where it should all the time, but it does move. This may be something the Controller needs to relearn or be taught by the dealer (reprogrammed).

To test if it is the Recirc door ask the following questions;
1. Does the amount of air moving out the vent (dash or floor) change when you change the speed of the fan? If yes, then its not the Recirc door.
2. Does the sound of the fan change when changing from fresh to recirc? If yes, then its not the Recirc door.

When the recirc door breaks, it falls down onto the fan intake and blocks about 90% of the air. The amount of air that passes doesn't change much with a faster fan and the noise doesn't change either.

What changes the noise when changing between recirc and fresh? When on Fresh, the door blocks inside air from getting into the fan suction, and also blocks fan noise from entering the cab.

I know a little bit about recirc doors as I don't have one.....anymore.

 

ok all of the above the awnser is yes........so what does that mean then? what could it possibly be if not the door??

 

It probably is the door. Which door? The mode door, not the recirc door. If it is the mode door, it is an expensive fix. You could go to http://www.hemitruckclub.com/ and peek at the manual for your truck to see just what DC expects to be done to do it right.

Good luck,