Blend Door Actuator Removal (Page 1/1)
V8Steve SEP 10, 08:36 PM
Much of the published material is about the difficulty on removing this actuator, especially separating the motor from the two link arms inside the ducting without losing them and the retaining clip. This thread is about how simple that repair was for me.

I previously had a problem with mouse nests. First it was inside the heater blower where they ate the plastic squirrel cage wheel. Then the heater fan ballast resistor ignited the clogged nesting material, etc. Eventually I removed nearly all the HVAC covering under the hood and removed all the nest material. Inside the car, I was seeing nest material under the defroster vent screens, etc. At the same time, I discovered the blend door was not responding to the dash controller buttons.

Using the Factory Service Manual, I determined the blend door actuator motor was not responding to correct signals from the buttons. After searching and reviewing every thread on this, including a very good video, it became obvious the actuator had to be replaced and it would not be an easy job. Since I also knew the interior side of the HVAC system still had mouse nesting inside, it would be necessary to remove the dash. Knowing the dash had to come out, I figured the blend door actuator would be much easier to replace.

Over the last 6 months, I'd removed the instrument cluster many times and had taken the console apart more times than I can count. Many years ago, I replaced the heater core and recalled it was not particularly difficult. The heater core removal played an important part of this blend door actuator replacement.

There are plenty of threads for removing the dash and I found it to be fast and simple with no complications. Keep in mind, I've already perfected the removal of the cluster and center console parts.

Here's the inside with the dash removed. It looks worse than it really is.



Heater Core Removal - There are 4 fasteners that hold it in. If the dash is in place, the uppermost fastener is accessible by removing the speaker.

Here it is:



The front, bottom, and rear fasteners are easy to find. Then remove the end cover and core bracket and it looks like the image below. This can all be done without removing the dash.



Mine was full of mouse nests



From this point, it was a simple matter to insert my right hand up into the duct and grab the two inside linkage bars. I used an offset blade type screwdriver to pull off the retaining clip. Even if you drop the clip and lose your grip on the two linkages, it's a simple matter to hold them again with your right hand. Meanwhile, by holding the door actuator with your left hand, it's a pretty simple swap.

All of this can be done without removing the dash. So, once you remove the radio, a few console panels, remove the passenger speaker, and finally remove the heater core compartment cover, you're home free. Reassembly was not difficult. In my case, I reconnected the battery with the cluster still out, etc. to make sure the replacement door motor functioned properly in all modes. BTW the door motor actuator was purchased "used" from this forum and works great. Thanks!

Hope this makes it easier for others to do this same repair.

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88GT 355 CI Sequential Holley Multiport , AFR milled 180, Dyno'd at 427 HP, 320 WHP
anderson@gdsconsulting.com

[This message has been edited by V8Steve (edited 09-10-2020).]

Archie AUG 20, 11:18 PM
This thread needs a BUMP
Will AUG 21, 09:23 PM
Handy info
theogre AUG 22, 09:56 AM
I Missed this when first posted...
Yes, Mice can get inside of car and live "downstream" of AC and Heater like shown above.
Can/Will screw w/ Air Flow and worse you Breath whatever crap that can put people in the hospital way before current virus panic.
If block enough Air Flow will cause AC problems, Blower problems or Blower Resistor Pack overheating.

⚠️ Warning:
If you see this above or not... always check the Blower Resistor Pack.
See https://www.fiero.nl/forum/Forum2/HTML/141959.html and search for more.

Leaves and Mice nest there can burn a car down.
Messed up air flow can over heat or worse as said above. Many Newer cars have "1 shot" thermal fuse that blow but not Fiero and Millions more vehicles from all car brands not just GM cars.
Over heating the resistor can cook the mounting board or melt the heater box and be very bad.

Even if you have a newer car... Check where the "resistor" is and check systems for trash problems. Many new cars have AC filters that get plugged too.
99% "1 shot" Thermal fuses are not installed to fix them. May have 1 or several depending on design of the pack.
Replacing a "Resistor Pack" can be very expensive part for them. "Resistor Pack" here because many are transistors etc cooled by H-blower same way that die for overheating even w/o a T-fuse.

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)


The Ogre's Fiero Cave

Jerseyshur OCT 26, 09:25 AM
does anyone know where an air door actuator can be purchased?
Gall757 OCT 26, 06:30 PM
You will have to get one off a junk Fiero. Ask in the MALL section of this forum I think you will have no trouble finding one.
cam-a-lot OCT 27, 08:32 AM
Great thread! Very helpful

Can someone post what the actuator looks like (photo)? I want to make sure I have a spare one

Not sure if they can be refurbished, as they are all more than 30 years old...
Duck 1 JUN 27, 07:50 AM
Do you have to remove the top dash to replace the blend door motor ?
V8Steve JUN 27, 07:57 AM
"The front, bottom, and rear fasteners are easy to find. Then remove the end cover and core bracket and it looks like the image below. This can all be done without removing the dash."
Duck 1 JUN 27, 01:45 PM
Thanks but I am still trying to figure out how to remove the blend door module.