Blend door actuator not working after heater core change
04-18-2011, 02:15 AM
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Blend door actuator not working after heater core change
I replaced my heater core today in my 99 F150 only to find that the vents would only blow cold air. I traced the problem down to find that the blend door actuator is not moving at all. I removed the actuator, and the blend door moves freely. I have tested voltage at the actuator, I get 12V with the key in the run position. I tested resistance at the actuator, the resistance changes as I turn the temperature dial. I took the actuator apart and turned the gears all the way to the "hot" side, as soon as I turn the key on, the actuator returns to it's previous position. I'm a little bit puzzled on this one, the actuator gets power, the potentiometer in the control panel appears to be working just fine, the actual motor in the actuator works just fine, but the 
thing will only stay in one position. Does anyone have any ideas? I suppose the actuator could possibly need to be replaced, but why would it go out at the same time that I replace the core. I did have the entire dash torn apart, so maybe I didn't put some wiring back together correctly, but everything seemed to go together just fine.
I hope this post makes sense, It's been a long day and I am pretty tired.
thing will only stay in one position. Does anyone have any ideas? I suppose the actuator could possibly need to be replaced, but why would it go out at the same time that I replace the core. I did have the entire dash torn apart, so maybe I didn't put some wiring back together correctly, but everything seemed to go together just fine.I hope this post makes sense, It's been a long day and I am pretty tired.
Last edited by SWI; 04-18-2011 at 02:18 AM.
04-18-2011, 02:56 AM
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These trucks are notorious for blend door problems.... The actuators going bad... Or the GEM module messing with it... .. If you search for GEM module or blend door actuator... You will find alot of threads... Some other guys that know more about it will probablyt be able to help you more... My 02 has problems.. I just have not got to it yet
05-11-2011, 10:57 PM
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Dekalb -
YOU ROCK!
The fix on my 1997 was too simple as well, #5 fuse. I was absolutly DREADING taking the dash out to do this. So after reading all these posts (I already had the black part on the floor ripped out) I tried plugging the new actuator into the wiring for the old, started the truck and nothing happened when I moved the temp control back and forth so I knew it wasn't getting power. Then I went to Ford Fleet and downloaded the owners manuel to see which fuses go to which and sure enough (my cruise doesn't work either, I just bought the thing a week ago) FLEW down to O'Rilley's and BAM the vents don't blow hot air all the time anymore and the cruise works now!!!!! 
TRY THIS FIRST!!!!
YOU ROCK!
The fix on my 1997 was too simple as well, #5 fuse. I was absolutly DREADING taking the dash out to do this. So after reading all these posts (I already had the black part on the floor ripped out) I tried plugging the new actuator into the wiring for the old, started the truck and nothing happened when I moved the temp control back and forth so I knew it wasn't getting power. Then I went to Ford Fleet and downloaded the owners manuel to see which fuses go to which and sure enough (my cruise doesn't work either, I just bought the thing a week ago) FLEW down to O'Rilley's and BAM the vents don't blow hot air all the time anymore and the cruise works now!!!!! TRY THIS FIRST!!!!
10-22-2018, 07:10 PM
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10-22-2018, 08:46 PM
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2014 is a different body style. You're better off in the correct forum.... this is for 97-03
