Hello,

I've read all the strings and have narrowed my problem down to the blend door actuator. Background: '99F150 80k miles. Heat leaking through vents on all settings, MAX and AC work on startup but then the vents turn warm/hot. I'm looking for a step by step procedure for replacing the blend door actuator. If nothing else, please help me locate it so I don't take my dash completely apart.

Thanks for any help.
CWill

 

Blend air door actuator is in the center of the heater case between the case and floor. Very basic instructions are unhook battery, discharge a/c, remove heater hoses,remove steering column, dash assembly, and heater case.

 

Turns out it was my blend door that was actually broken. I didn't have to remove the entire dash (i.e. drain the heater core or the evaporator.) I wouldn't have had to remove the entire dash to pull out the blend door actuator had that been the problem. I took the dash apart while still mounted in the truck which wasn't too difficult but I do recommend taking sequential still photos or use a video camera (like I did) so you will know which piece/screw goes where when you put it back together. Anyway, I called the dealer about the replacement blend door. They no longer sell just the blend door by itself. You have to buy the entire box which contains the heater core and the evaporator (about $350.00). After no success with local junk yards, I took the door out, repaired it with epoxy and reinforced it. I put the door back in and cycled it about 30 times before deciding that the epoxy would indeed work. One important thing I learned is that this is definitely a manufacturer's defect. In order to keep from having this happen you should not turn the blend switch all the way to cold or hot. Doing this puts too much torque on the plastic joint where the blend door mates to the blend door actuator. If you are having the same problem, I'd be happy to give you advise.

CWILL

 

Sounds like a great repair to the blender door. I have a 98 Gulfstream motorhome on a F-350 Econoline Van chassis with the same problem. I just got into this yesterday afternoon and found the problem. It seems I can't get to the blend door without removing the heater core and that looks like a major problem because the Ford Springlock clamps require a special tool to remove and I have read they are prone to leaking especially after removal and reassembly.

My question, was your blend door right behind the heater core? My heater box is on the passenger side under the dash. You remove the plastic housing then you are able to see the heater core, but can't pull it out far enough to get to the blend door without disconnecting the heater cor hoses which you are accessed from under the hood.

Any help would be appreciated. The entire heater box is $143, but if I have to take it to a dealer the labor I'm sure will be another couple hundred dollars.

Thanks,
Bob