No defrost
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Elder User
Joined: Aug 2009
Posts: 946
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From: Clearfield County, PA
No defrost
I just realize that i have no defrost. When i put it on that button or the feet/defrost they all come out the front vents and nothing comes out the defrost ports. What might be the issue here? Thanks
Laughing Gas
Joined: Aug 2012
Posts: 915
Likes: 3
From: Palatka, FL
Loss of vacuum due to leak or cracked vacuum line. The vacuum canister is on the passenger fender well under the hood. Look at all your vacuum lines under the dash and listen for leaks. Also the flapper valve that changes the positions of the vents may be stuck. Vacuum is used to move the flapper valve. Look at all. If you have 4x4 and it is Shift On The Fly then check if it will engage. These engines do not create vacuum so there is a vacuum motor/pump that creates it.
Check fuse 24 under the steering wheel. It should be a 10 amp fuse that powers multiple items. One item is the Blend Door Actuator.
That is as close as I can do for now until you give us some feedback.
Start the truck. Turn on fan. Listen really well at the passenger side foot well and change the position of the vent control switch. Can you hear the flapper valve moving? Do you hear a vacuum leak somewhere?
Give us some feedback.
Dwayne
Check fuse 24 under the steering wheel. It should be a 10 amp fuse that powers multiple items. One item is the Blend Door Actuator.
That is as close as I can do for now until you give us some feedback.
Start the truck. Turn on fan. Listen really well at the passenger side foot well and change the position of the vent control switch. Can you hear the flapper valve moving? Do you hear a vacuum leak somewhere?
Give us some feedback.
Dwayne
Hotshot
Joined: Jan 2011
Posts: 18,849
Likes: 179
From: Puget Sound
Clarification: The engine is "fly by wire" - meaning the computer controls how and if it runs. There are no cables or mechanical interlinks like a conventional throttle.
The vacuum operates two things, and that's it: 4X4 hubs and the cab vent system. When there is no vacuum, the system defaults to defrost... this symptom is how we know we have a vacuum leak, a bad vacuum pump, or a 4X4 hub lock problem.
Back to the original problem of no defrost: This is unusual, it may be a stuck air diverter.
https://www.ford-trucks.com/forums/1...cuum-pump.html
The vacuum operates two things, and that's it: 4X4 hubs and the cab vent system. When there is no vacuum, the system defaults to defrost... this symptom is how we know we have a vacuum leak, a bad vacuum pump, or a 4X4 hub lock problem.
Back to the original problem of no defrost: This is unusual, it may be a stuck air diverter.
https://www.ford-trucks.com/forums/1...cuum-pump.html
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