Why does the Blend Door Actuator initialize and then it gets stuck in one position?

Tiny
SHARPIE_DA_P
  • MEMBER
  • 1997 ACURA CL
  • 3.0L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 160,000 MILES
Having a weird issue. My blend door actuator stopped working completely a few weeks back. So, I removed it and popped open the assembly and cleaned off the smeared grease as well as I could off the gears and PCB board and contacts. I couldn't visually see anything wrong. The teeth on the gears were all intact and everything spun as it should.

When I reassembled and installed, the actuator arm would spin endlessly as soon as the ignition was put in the "on" position. It would not stop spinning, no matter what buttons I pressed on the climate control panel.

So, I uninstalled and opened it back up again. This time I noticed that the positive and negative posts for the motor didn't seem to make good contact with the mating pins, so I bent them slightly, so they were connected again. I also slightly bent the electrical contacts for the wheel to ensure full contact, and applied Dialectric grease to all of these surfaces.

When I reinstalled, instead of spinning endlessly, this time the actuator arm initializes. Then goes to a particular position. But it does not respond to any commands from the climate control panel. I've tried every combination of buttons to try and get the arm to move again. Nothing.

So, I disassembled and tried changing the orientation of the arm then reinstalling. No matter where I seem to place the starting position of the actuator arm, as soon as I turn the car on it always rotates back to the particular position as shown in the picture. And will never do anything else.

This stumps me. The internal circuitry seems rather simple. Just a motor and electrical contacts on a wheel that allow it to move with commands. Since the arm spins every time, I'm assuming the motor itself is fine. But something else is wrong.

Here's the bad part: when I disassembled the first time, I forgot to note the exact orientation of the arm. Does the arm HAVE to be reinstalled into a certain position for it to work correctly? Or will the system automatically re-initialize and recalibrate itself into the proper position once plugged in?


I'm unsure if my vehicle has a reset/recalibration procedure for the blend door motor. Perhaps my actuator is broken, but curious if there's anything I should be looking out for before I buy a replacement unit? Thanks!
Sunday, July 24th, 2022 AT 7:21 PM

1 Reply

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,904 POSTS
Yep, the arm position, the system automatically re-initializes and recalibrates itself into the proper position. But it sounds like the potentiometer is not working inside the blend door actuator which happens. I would get a new unit and replace the old one. Here are the instructions to help you install it correctly in the diagrams below. Check out the diagrams (below). Please let us know what happens.
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Monday, July 25th, 2022 AT 11:09 AM

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