zmad5306 Posted September 7, 2018 Share Posted September 7, 2018 (edited) I need some help with some issues with the blend door on my mom's 2012 Fusion. She has had it to a couple of mechanics and they have been unable to find the issue as its intermittent. The AC will run ice cold for a spell (1 to 5 minutes) then kick over to full heat. When this happens the blend door actuator is turning the blend door over to full hot (I had my finger on it when it happened). It doesn't appear that the door is slamming closed like the gears are stripped. It slowly moved as if operated by the actuator. Once this happens it will blow full hot until you restart the car. Here is what I have tried so far: Replaced blend door actuator. Calibrate the blend door actuator with a battery disconnect (several minutes). Calibrate the blend door actuator by removing fuse 15 for 30 seconds, turning on the ignition for 30 seconds then replacing the fuse and turning on the ignition for 30 seconds. Disconnecting the blend door actuator and manually turning the blend door to cold. Blew cold for at least 15 minutes. I needed to cool off its about 90 out. At this point I am convinced that its a blend door problem (see 4th bullet above) and the compressor and radiator fan never kick off. It appears that turning off recirculate/max AC, changing the cabin pressure by rolling the windows up/down and changing the temperature setting all trigger this behavior. The blend door is not easy to turn manually when the blower is on full blast, with the blower off its fairly easily turned by hand (no tools). It almost appears the calibration cycle might be causing it to stick in hot. Anyone have any thoughts on next steps? Edited September 7, 2018 by zmad5306 0 Quote Link to comment Share on other sites More sharing options...
eGuru Posted September 8, 2018 Share Posted September 8, 2018 Replace the HVAC controller. 0 Quote Link to comment Share on other sites More sharing options...
zmad5306 Posted September 8, 2018 Author Share Posted September 8, 2018 That was my next guess. I am going to test the leads to the actuator to see if the potentiometer for the temperature control is working. 0 Quote Link to comment Share on other sites More sharing options...
eGuru Posted September 8, 2018 Share Posted September 8, 2018 3 hours ago, zmad5306 said: That was my next guess. I am going to test the leads to the actuator to see if the potentiometer for the temperature control is working. Measure the voltage across the potentiometer. Make sure you are seeing the 5.0 V reference voltage. 0 Quote Link to comment Share on other sites More sharing options...
zmad5306 Posted September 8, 2018 Author Share Posted September 8, 2018 Which pins are the potentiometer? 0 Quote Link to comment Share on other sites More sharing options...
eGuru Posted September 8, 2018 Share Posted September 8, 2018 5 hours ago, zmad5306 said: Which pins are the potentiometer? The group of 3 smaller diameter pins. 0 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.