Replacing the left blend door actuator?

BSYEARSLEY

MEMBER
2011 HONDA ACCORD
3.5L
6 CYL
2WD
AUTOMATIC
260,000 MILES

I have the car listed above EX-L with dual zone HVAC. The passenger side only blows cold air when in heat mode. I removed the blend door actuator which was a Dorman part 604-935 147 22220. While it was removed, I could access the arm for the flap, and confirmed when I moved it up, hot air would come out passenger side vents. Also, when I changed the temperature from cold to hot it would move about 45 degrees in a counterclockwise direction (when looking at the arm on actuator). So, it seems to be working, but since I purchased this car used and never used it when it was cold, I'm not sure it ever has worked correctly since I have had it. I reinstalled it in the cold position (when I set air to lowest temp) and when flap is in position to just blow cold air. I can see that I have the actuator pin in the slot of the flap arm when re-installed, but when I test, I see it moving on the flap arm but it's not moving up to close the flap for hot air. So, my question is, is this Dorman actuator the correct part, should it move more than 45 degrees? Or am I installing it incorrectly?

Tuesday, January 21st, 2025 AT 8:20 AM

6 Replies

BSYEARSLEY

MEMBER
6 POSTS

Here are some pictures of the actuator.

Images (Click to make bigger)

Was this

answer

helpful?

Yes

Tuesday, January 21st, 2025 AT 8:23 AM

STEVE W.

MECHANIC
14,514 POSTS

That actuator looks like the one for the recirculation door. The OE part is 79170TA5A21 however Dorman claims it will fit. However, I avoid their parts if at all possible, to the point that I'll go get a used one instead of theirs. As for the installation, the lever should be down and the pin on the motors arm goes in the slot. I don't see any programming needed for the replacement. One thing to try, run the engine up to temp and then flip the lever and see if it now blows heat. If it does, then the actuator is likely the problem. If there is no temperature. Change then it could be a bad heater core.

Images (Click to make bigger)

Was this

answer

helpful?

Yes

Tuesday, January 21st, 2025 AT 9:41 AM

BSYEARSLEY

MEMBER
6 POSTS

Thanks for the quick reply. I was able to run the engine to temp, and when I flip up the flap lever, I do get heat on the passenger side. I always had heat on the driver's side. The picture I sent of the actuator was installed in the position you show in the diagram that you sent above. Did Honda ever install Dorman actuators, or did a previous owner replace the Honda OEM actuator?

What position should the pin be on the actuator be when installing (assuming the lever on flap is down in cold position), 3:00 like shown in the picture you sent? Also, any idea how many degrees the actuator should rotate from cold to hot?

I ordered a new actuator, which should arrive by this weekend so I can install and test. Will let you know what happens.

Was this

answer

helpful?

Yes

Tuesday, January 21st, 2025 AT 10:48 AM

STEVE W.

MECHANIC
14,514 POSTS

Honda never installed Dorman anything. Dorman does make some OE parts but not for Honda. For me a Dorman part is basically the last item I want as they have a very bad reputation in the shop community. For the DIY they look like a lower priced part and they are, however they also live up to the phrase "You get what you pay for" I've had people bring me their parts and I will warn them up front that when they fail it will cost them more that the OE part to replace it again. In the case of actuators, I've seen them fail in under 2 months. Likely this was a case where the OE part failed from age and they shopped by price for the new part. Being it isn't that hard to get to it might not be a bad result if you have to replace a 25-dollar part every 2 years instead of a 75-dollar part every 15 years. That is why Dorman exists.
You want the door in the cold position, don't connect the new actuator to power until you have it installed. It has a position sensor in it, and it will adjust itself once installed and powered on. That actuator should rotate far enough to cycle the door fully open and closed. That is actually how they calibrate. The system looks at the current draw of the motor, when the door fully closes the current spikes, and the systems processor turns the motor off. Now it reverses the polarity, and the door swings the other way until it stops. The processor then looks at the count from the position sensor. Let's say it moves 100 steps from end to end. The control module now knows how many steps to move the door in response to you setting the temperature control.
What I see in many aftermarket parts is that they use a motor that is out of spec or a sensor that reads wrong. Both create problems. Especially if you open them up and see how they are made.

Was this

answer

helpful?

Yes

Tuesday, January 21st, 2025 AT 5:37 PM

BSYEARSLEY