TLDR: Air does not like to come out of the vents consistently. I have to reset the AC by disconnecting the battery every 2-3 weeks. Will a Blower Motor Control Module fix my issue?
Background: About 6-8 weeks ago, the AC stopped blowing from the forward-facing vents. It would only come out of the foot and defrost vents. We live in Houston so that would not work for the summer so I started researching.
I could hear the clicking under the dash and everything I read at the time said this was a blend door actuator motor issue, and the only way to get access to the motor was to pull the dash. Some people mentioned that they could get to it behind the instrument cluster but it was difficult if you have big hands. I haven’t missed many meals so I decided to pull the dash…
I thought I had it installed correctly with the arms for the vents in their correct channels, but when I got it back together, it did not work properly. In trying to figure out how to fix that issue, I learned that I could actually get access to the blend door motor from under the dash. With a little Phillips screwdriver, a headlight, and remembering some of my training when I was a performer for a traveling Magic Mike Review Show, I was able to get in position to pull the motor and reinstall it in the proper position.
LESSON LEARNED – Install the blend door actuator motor with the AC on and the motor connected. I found that upon killing the engine/starting the engine, the AC doors go back to a “Home” position. So putting the doors in their position, and the control panel matching the position, then turning off the car…the motor will return to its original state, and the channels will not line up with the doors.
SO…I connected the motor to its plug, started the car, and had my wife cycle through the modes and observed motor operation. Everything looked great! We set the panel to forward vent, the motor moved into position, and I adjusted the doors so that airflow would be directed forward. The motor slipped easily into place, I replaced the 3 screws and checked for operation. Everything was great! I fixed it!
Not quite.
After a few weeks, the old behavior returned. Long story short, I found a troubleshooting guide from a Subaru manual that said the primary culprit was the Heater Control Assembly. So I shopped around my local Subbie dealers for the best price and ordered it. When it was delivered, I installed and everything was great. I fixed it!
“Oh, my sweet summer child…”
The condition returned, AC through the foot or combination foot and defrost. On occasion, air would come through the vent and then switch on its own. The interim fix has been to reset the AC by disconnecting the battery, discharging the capacitors, and then reconnecting the battery. I would then touch the Start button but not depress the brake and let the radio go through its startup process. After a couple of minutes, I would start the car and let it run for a few minutes until it calmed down and relearned how to idle. After this process, the AC worked as expected…
…For a few weeks, then it would return to its old behavior. It doesn’t make sense that everything works great for a period of time, and then it’s not right (Hank Hill voice.). It seemed to me that there was something controlling the motor and its position.
Thanks to this site, while reading another post, I saw the mention of a control unit for the HVAC. As I was researching, the air again refused to come from the vent. My response was to pull the blend door motor and leave the doors in the vent position.
(I didn’t know the post would be this long; I hope it helps someone)
But before I pulled it out completely, I ran through the modes and recorded a video for everyone. Sorry about my voice.
I don’t know if you can hear my wife clearly, but the Vent and Floor/Vent settings make the motor vacillate and quiver. Setting to Feet and Defrost seem to work perfectly. I can feel that the airflow from the vent is not smooth like the doors are in between positions.
So finally the question: Will a Blower Motor Control Module fix my issue? Does the control module act as an ECU for the HVAC system? I REALLY do not want to take this to the dealer.
Thank you for reading this. I wanted to share my experience with this issue and I sincerely hope that this will help someone in the future. I appreciate what anyone has to say!
