My Recent Brush with the Blend Door Problem

[JOEZ33]

Recently I've been having random problems of warm ac, and then after about 10 minutes the normal fridgid AC that this truck has always been good for. I recharged it and it was only 4 oz low, pressures normal.

Now today I have nothing but scalding hot air, no ac at all. Even with it turned all the way down it's blasting burning hot air instead of cold air, -Not even outside cool air.

The EATC diagnostic gave me a 025 code. I pulled the actuator and observed it while it was electrically connected during the self test, it works fine. The door however........... I think the door is screwed. I took the actuator apart, used the main gear and actuator arm to manually move the door, but it doesn't feel like it's connecting to anything at all. I think the door is broken and tomorrow I'll cut an access panel into the box to look at it some more.

My observation for today though was that right after starting if I select "Max AC" it gives me ice cold air instead of burning hot air, however if I touch ANY of the buttons or change the fan speed on the head unit I instantly lose the cold air. If I select "Max AC" again, nothing happens- and it stays blowing super hot air, I drove with it like that for 20 min to see if the heater core would cool off again and it doesn't. This leads me to believe that I my heater core supply valve is malfunctioning, or it's got a design flaw. Normally on "Max AC" its supposed to shut off the hot water from going into the heater core.

I've seen photos of how the blend doors fail on the F150 forums. They seem to crack at the point where the actuator locks into it. Looks like a simple fix to me, with a little bit of creative planning. I guess tomorrow I'll make my own attempt at fixing it and add it to the 150 topics already listed on this forum.

 

[my98nnj]

Max A/C doesn't send any air past the heater core.
Changing the fan speed should have no effect on the air temp either.

Definately sounds like a door(s) issue, but it might be more the just the blend door.

 

[rollinstone]

Just follow the blend door replacement "sticky" in this forum...works like a charm. If the door isn't responding to the actuator it means the top hinge portion of the door is cracked/broken. RockAuto.com has a blend door replacement kit for about $20.

I took the easy approach and cut out the bottom of the plenum chamber. The broken door simply dropped out. I snapped the new door into place (there should be an audible *snap* when installing the new door). The new door will hang from the actuator shaft so you can check it's operation before taping the cutout back into place.

I've got heat AND ac! Most of all I saved about $1000! All told about 2 hours of work, if that.

 

[kgdotcom]

Just follow the blend door replacement "sticky" in this forum...works like a charm. If the door isn't responding to the actuator it means the top hinge portion of the door is cracked/broken. RockAuto.com has a blend door replacement kit for about $20.

I took the easy approach and cut out the bottom of the plenum chamber. The broken door simply dropped out. I snapped the new door into place (the should be an audible *snap* when installing the new door). The new door will hang from the actuator shaft so you can check it's operation before taping the cutout back into place.

I've got heat AND ac! Most of all I saved about $1000! All told about 2 hours of work, if that.

Just did mine today was a snap. Routed out the triangle in the plenum and bent it down took to out the old in with the new bondo'd it back up and heat heat heat!