Hello,
I have an '03 F-150 Super Crew with the climate control. While I was hunting this year, the floor vents just stopped working. When I press vent it thinks for a sec, and then blows out the Defrost. Any ideas ????

Thanks for the help.
Ben

 

Defrost is the default position. Not real familiar with the EATC you have, but in conventional systems this usually indicates a leak in the vacuum line.

 

I took out the controller module (where I change the temp and fan etc) and can't see any leeks or bad connections, checked the relays with a meter and they are all getting voltage and are picking up. I couldn't get to/find the spot that the floor heater connection is.

It almost seems like there is somthing blocking the vent from changing to the floor, it seems like it is trying, but then it gives up and goes to the defrost. Hope that helps more.

Ben

 

Hi Ben and welcome to the forum

Like MrBSS said i think you have a vacuum leak too.
Under the hood, on the passenger's side, you'll see some vacuum hoses. Check all of them to make sure there are no broken or disconnected ones. There is also a vacuum reservoir behind the battery tray. They leak sometimes.
If you have a vacuum pump you can apply vacuum manually to the different lines, reservoir etc and see if they hold it.

 

i believe it is a gray plastic hose that goes down beside the airbox that usually gets heat cracks, you can patch it with some rubber hose that fits snugly...if its just a small leak, duct tape will work til it warms up a bit

 

passenger side firewall, you will see a small hose go thru the firewall. TEE on the eignie side. TEE goes to a canister behind the battery, an dto the manifold for vacuum. The vacuum pulls a cylinder opne and strokes the plastic door to direct air to top or bottom louvers. if it fails, it goes to defrost.

 

I have time this afternoon to chech the above metioned hoses. Thank you for your help.

I think that I should have given more information, and that is that I am able to change from defrost to the vent, or vent and defrost, just not anything that involves the floor, so to me it would seem like it is just isolated to the floor flap (or whatever changed to this setting.)

Thanks for the help.

Ben

 

My 97 has the manual ac controls. But I had a similar problem and the door came off its tracks... or something along those lines, or the motor actuator arm or something was disconnected, it was under the dash thats about all i know.

 

I just replaced the heater core in my truck, and it's only blowing out of the defrost vents as well. I think it's coming from the vaccume lines that connect near the throttle pedal. They are loose as can be inside the connector right there.

Either way....that dash is NOT coming out again!!