2010-2016 HVAC Blend Door Replacement without removing the dashboard (Hack) - TerrainForum.net: GMC Terrain Forum
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post #1 of 5 (permalink) Old 10-11-2019, 02:09 PM Thread Starter
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2010-2016 HVAC Blend Door Replacement without removing the dashboard (Hack)

2010-2016 HVAC Blend Door Replacement without removing the dashboard (Hack)

It started with the familiar clicking failure
When I picked up my used 2010 Equinox LT AWD it already suffered from a blend door adjustment issue – I could either get full hot or full cold temps.
Finally last spring the temperature adjustment only gave me COLD air (not nice in April in Michigan!)

I assumed (incorrectly) that the blend door actuator finally failed – well it did but I had a more serious problem.

I removed the actuator and started to re install the new one. I tried to adjust the blend door to mate to the new actuator.
I grabbed the hinge and it felt very loose. Then it happened. The hinge fell into the housing, and the blend door fell helplessly into the bottom of the housing.

I waited until August and started investigating what it would take to get this fixed.

All forum posts led to the removal of the entire dashboard to access the HVAC housing.

This was not something I wished to tackle on my own.

I received 3 quotes ranging from $1400 - $2800 – not something I wanted to invest in a 9 year old vehicle.

I decided the vehicle was worth more to me than trading-in and taking on another car payment at this time.

Couldn’t I just hack into the side of the housing, pop out the old blend door, then epoxy it all back in?

Yes!

The following are my successes and mistakes for you to repair this on your own.

You will need:

Dremel tool with cutoff blade
New blend door GM#20785622 (I bought at https://www.carid.com/acdelco/gm-ori...0&url=10224384)
New blend door actuator or new spur gear (if you want to repair the old one)
Hack saw blade
Utility Knife
Needle nose pliers
Philips screwdriver
JB Weld Plastic bonder Epoxy body filler
1/4” and 9/32” sockets socket wrench and extensions, and ¼” box wrench
Pads to kneel on and protect your ribs from the passenger seat rail
Powerful worklight
New Cabin air filter (Optional)

Blend Door Replacement Pictures
Slide 1 – Exploded view of the HVAC Housing
Slide 2 - The Cutout Views
Slide 3 - The hinge on the blend door actually snapped off in my case.
Slide 4 & 5 – If I were to do it again - avoiding the heater core
Slide 6 & 7 – Re-Assembly parts
Slide 8 - 10 – Re-Assembly views
Slide 11 – Fuse removal for calibration



Disclaimer - Start by removing the Negative battery cable.

Move the passenger seat all the way back (alternately remove the whole seat)

Remove glove box – open it and flex the top of the glove box under the stop tab. Pull up on the hinged side and it pops out.

Removal of passenger side trim panel beneath the glove box area is done with a 9/32” socket.

Remove the electrical harness in the area. There are several clips and fasteners to remove from the blower housing and the HVAC housing. Unplug the blend door actuator, blower motor, and blower motor controller and tuck the harness out of your way to continue.

Remove the Blend door actuator removing three ¼” hex head screws.

I removed the blower motor from the housing for better access – held in place with three ¼” hex head bolts

I purchased the new blend door (Online link above) and a new blend door actuator at O’Reillys

I mapped out my cutout with no information on the insides of the HVAC housing (GM calls it the ‘Evaporator case’) except some crude diagrams found online.
Picture HERE

The heater core and the A/C Evaporator core are BOTH inside this housing.

My plan was to cut out around the blend door hinge socket and enough towards the front of the vehicle to be able to remove and re-install it through the side of the housing.

I wanted to keep two of the three actuator mounting posts in place, so the actuator, when replaced, would still be on plane.

Taking the new blend door I mapped out the path the Dremel tool would follow with some duct tape.

I had to cut off some tabs at the rear of the cutout, used to secure the wire harness, to get the cutoff wheel into the back side.

There is a sensor in the rear of the housing – towards the firewall. I stayed in front of that – it is a long pencil type sensor that extends in front of the AC Evaporator.

The initial outline cut should only go deep enough to get through the housing.

Take your utility knife and make sure you have gotten through everywhere.

If I were to do it again – I would cut along the ridge (PPT shows alternate cutout lines now that I know what is behind ) and not cut through the ribs or get close to heater core.
If you do decide to cutout the same as I did, take care not to nick the heater core with Dremel tool cutoff wheel.

I pried out the housing. As you see in the photos, I cut just above a ridge that connects to the opposite side of the housing. That makes it a bit difficult to remove. Once the upper portion was out, because of the lower cut line I made, it was still attached to the heater core ribs

The ribs on the inside of the housing were back cut with a loose hand held hack saw blade (I wrapped some duct tape around one end and used it like a ‘hand’ saw).

Now that you have access inside the housing, you can remove the old blend door and any broken pieces you may have inside.

Blend Door Replacement Pictures
Slide 1 – Exploded view of the HVAC Housing
Slide 2 - The hinge on the blend door actually snapped off in my case.
Slide 3 – The Cutout
Slide 4 & 5 – If I were to do it again - avoiding the heater core
Slide 6 & 7 – Re-Assembly parts
Slide 8 & 9 – Re-Assembly views
Slide 10 – Fuse removal for calibration

To set the depth of the cutout piece, the baffling straps were removed from the old blend door with Dremel tool
Clean the edges of the cutout portion with a utility knife.
These will be used to set the depth of the cutout portion when Epoxying back into the housing. See picture showing the straps epoxied in place prior to re-assembly.
I also used the Housing from old actuator to orient the cutout portion properly during epoxy.


Re-Assembly
Insert the new blend door using the ½ round as a guide into the socket at the other end
Dry fit the cutout portion guiding it into the blend door hinge and the socket in the opposite half of the HVAC housing
Make sure the blend door moves freely. Note there will be some resistance due to the molded rubber gasket on the blend door.
Take the straps cut from the old blend door and match mark the location you will pre-set them on the cutout portion.
Remove the cutout portion to affix the straps.
Mix enough of the JB Weld to attach the straps. Work time is around 15 minutes.
When the straps are set, you can again dry fit the cutout portion guiding it into the blend door hinge and the socket in the opposite half of the HVAC housing.
Now also use the old Actuator housing to align the cutout by aligning it on its’ mounting posts. Secure one screw to attach the actuator housing on the cutout.
Make sure the blend door moves freely.
Mix enough of the JB Weld to work in 15 minutes. The material will stiffen up after ~5 minutes when working on vertical surfaces.
I mixed three or four batches to get all the way around the cutout portion.
When the first batch or two sets up, swing the actuator housing out of the way and finish the sealing.
Make sure the blend door moves freely throughout the process.

Re-install the blower into the housing.
I waited thirty minutes to perform a pressure test on the repair.
Start the vehicle and turn the blower on. Re-coat any epoxy repairs if needed.

Hooray – I have heat again!!

(Dis-claimer) Remove the Negative (black) battery cable.
Alternately, I removed the HVAC 1 and HVAC2 fuses.

Re-install the blend door actuator. (Fun Note – the one I purchased was assembled incorrectly. I had to dis-assemble and turn the actuator gear so that it would mate to the blend door hinge and the actuator mounting posts.)

Plug in the actuator.
Re-install the wiring harness.
Re-install the fuses.

Turn the ignition switch on. The actuator will go the a calibration cycle.

Start the vehicle.
Turn off the blower.
Adjust the temperature and check that your actuator is cycling through the range of motion.

Mine creaked at the extreme Hot and Cold settings so for now I will adjust to the extreme position and back of a few clicks. (This may be due to the new Blend door seal not being formed in yet.)

While you have the glove box out – replace the cabin air filter

Reinstall the lower trim panel and the glove box.

Writing this a few weeks later, and all is still well.

Good luck if you attempt this, and post your results!
Attached Files
File Type: pdf equinox2010.pdf (1.11 MB, 19 views)
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post #2 of 5 (permalink) Old 10-11-2019, 03:27 PM
Theta GOD!
 
Join Date: Jan 2010
Posts: 9,642
Excellent write up.


But, I would expect nothing less from a fellow "ski".


Why do Polish names end in ski ? Because we can't spell toboggan.
garagerog and jgski like this.

2018 Equinox LT1 1.5 L 4 cyl, AWD, S/R Cajun Red Tintcoat/Black

2010 Equinox LTZ 2.4 L 4 cyl, FWD, S/R Cardinal Red/Black
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post #3 of 5 (permalink) Old 10-11-2019, 10:07 PM
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Join Date: Feb 2011
Posts: 3,208
Good job! I remember reading a similar cut-out job for my ‘97 Taurus to remove the heater core without ripping out the dash.

Why can’t they design these things for easier repair access - like maybe remove a heater core out the engine compartment side?

My 2011 V6 has the thumping noise in the dash - sounds like a “little person” in there punching and kicking to get out. Only does it for about 10 seconds on startup. Been doing it for about a year now. Not doing anything about it until I absolutely have to.

There was a time with my Taurus where I would manually prop the door up under the dash to get heat during the winter. Did that for a few years before finally fixing it.

Oh - can’t see any of the pics (on my phone app). Are they not attached yet?

2011 Equinox 1LT (new Jan 2011): Summit White / 3.0 L V6 / FWD / Pioneer Stereo / 18" Wheels / 138.2k miles [05-NOV-2019]

2002 Impala 1LT (new Jun 2002): Summit White / 3.4 L V6 / FWD / Cassette-CD Combo /225.5k miles [05-NOV-2019]
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post #4 of 5 (permalink) Old 10-17-2019, 01:20 PM Thread Starter
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Join Date: Apr 2019
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Hi
There is a PDF attached
Must not be seen in the App?
Gary
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post #5 of 5 (permalink) Old 10-17-2019, 02:24 PM
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Quote:
Originally Posted by jgski View Post
Hi
There is a PDF attached
Must not be seen in the App?
Gary
Huh! I see it on the desktop (now) but the iPhone only shows the first slide. Can't swipe to the ones after it, for some reason ...

2011 Equinox 1LT (new Jan 2011): Summit White / 3.0 L V6 / FWD / Pioneer Stereo / 18" Wheels / 138.2k miles [05-NOV-2019]

2002 Impala 1LT (new Jun 2002): Summit White / 3.4 L V6 / FWD / Cassette-CD Combo /225.5k miles [05-NOV-2019]
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