Blend Door Fixed!

[CamaroBarb]

I simply removed the HVAC fuse for 30 sec then put it back in, all the doors started moving for a few mins back and forth. When I did the relearn it stopped the crunching noise I was hearing every time I got in the car and the blend door cycled. I'm at 87k and no broken door yet but time will tell.

[MBERR3]

I am replacing my blend door and I am needing to know how to remove the body control module under the drivers side dash

[Jbcamaro]

I’m not sure if this has been answered yet .... I just finished the blend door install but I still have no heat . My actuator does work and I made sure I aligned it all back together properly. Any help would be greatly appreciated . I’ve been without heat now for 5 years and just now go the chance to do the install .

[The Flash]

Originally Posted by uvraise

So, I made this repair yesterday. It wasn't fun, at all. It took me about 5 hours soup to nuts. I used the link below as a guide to do the repair. Thanks to 737mechanic for the video! If you're going to do this repair yourself, I suggest you watch this video.

A few things to be prepared for.

Remove the front seat: ....

I hope these tips help someone to make the repair a little easier. If anyone has any questions, feel free tom ask. I didn't take any pics or video as there's enough out there. I thought I'd just give my experience to help others.
By the way, the repair works awesome!

Very generous of you to take the time to write this guide. Thanks. I might need it in the future.

All the best and drive safe!


The Flash

[blumaro]

uvraise,

Thank you for posting this back in 2020. My blend door failed back it 2018 at ~42,000 miles. There were videos on Youtube then that showed this repair technique but they were not that good and missing some details. I didn't attempt the repair at that time and had the dealership fix it for ~$1,300 with some assistance from Chevy Customer Service. Started a thread about it located here:

https://www.camaro5.com/forums/showthread.php?t=528157

Fast forward to last week, while driving home from work I noticed warm air blowing from the vents yet the temperature was set to cold. AC was off and I was just bringing in outside air. Got home and pulled into the garage and shut off the engine. With the key in the run position I cycled the temperature knob and heard the grinding sound. Yep, another blend door bites the dust. @*$^@&!!! GM! The car has ~72,900 miles on it now.

I proceeded to crack a beer and hop on Camaro5 to see the latest blend door guidance and found your thread. Great write up. You filled in many details that were lacking back in 2018 and the link to 737mechanic's Youtube video was very helpful. I will re-link it here:



I found another video that was helpful as well:



In Robert Green's video, he used a Dremel Multi Max saw to cut the HVAC box.


With this wealth of new information I decided to inflict this repair myself. No way was I paying the dealership for this again. I don't own a Multi Max saw so the hot knife method was the cheaper option and I figured it would be more controllable.

CamaroBarb posted a link to the Harbor Freight hot knife in post #40 of this thread. Thanks CamaroBarb! I will re-post a link to the hot knife here:

https://www.harborfreight.com/130-wa...ife-60313.html

Amazon has the blend door for $15.22 with fast shipping here:

https://www.amazon.com/dp/B0031IBS0O...roduct_details

The blend door arrived last Thursday. Friday after work, I hit Harbor Freight for the hot knife and a yellow paint pen. Yesterday morning I grabbed a tube of Permatex black RTV at Autozone. Then it was off to Joe Canal's for some beers and a bag of ice. I ate some breakfast and convinced the wife to assist me with the repair. As expected it worked out well to have her feed me tools while laying under the dash.

Yesterday it was a lovely 77 deg. F and sunny. Unusual for NJ in November, but I'll take it. I started a 1:00PM with keying the ignition to the run position and setting the temperature knob to full hot then keyed it off and removed the key.

Then the driver's seat was removed. I padded the floor with some bath towels and a seat cushion from my porch chairs to avoid having the driver's seat electrical connector jammed into my back for the duration of the repair. This worked out well, not real comfortable but tolerable.

The two screws that secure the duct were removed next. With the duct still in place I dropped the BCM and disconnect all of the BCM plugs. I was able to slip the BCM out of it's bracket and had to rotate it to extract it.

With the BCM out of the way I was able to remove the duct. Please note that the BCM and duct are squeezed in there and it will take some patients to figure out the disassembly order. I also removed the BCM plastic mounting bracket.

The BCM wire harness was dangling in the way so it was temporarily zip tied to the lower portion dashboard under the steering column.

The gas pedal plug appeared to be in the way so I unplugged that. That's when I noticed that the dealership left one of the bolts securing the HVAC box to the body loose so I tightened it up. Thanks Turnersville Chevy, you guys suck and you still owe me a roof ditch molding. Oh, and remember the time you changed the oil and only put 5 quarts back in? Yeah, you suck. I might just show up tomorrow morning with the broken blend door and create a scene in front of the other service customers. Sorry to go off on a rant.

Next, I removed the blend door actuator plug and stuck it up higher in the dash so it would be out of the way. The screws that secure the actuator (and the portion of the HVAC box that gets cut out) are 5.5mm. That's when I noticed that I do not own a 5.5mm 1/4" drive socket. No problem, a 7/32" socket works just fine. I removed the actuator and pulled out the white drive nub (yes, nub - I'm an mechanical engineer and that's what I'm calling it). Swapping my engineer's hat for a proctologist's hat, I inserted my index finger in the blend door hole to feel the jagged, broken plastic of the four year old $1,300 blend door. Failure confirmed.

This is where the new, post 2018 information gave me the confidence to attempt this repair. The two linked videos clearly show where the HVAC box cuts need to be made. I marked the cut lines with the paint pen. Then summoned the wife.

The wife unit was necessary to carefully receive the hot knife when I was done making the cuts as the knife was still really hot and I needed both hands to pull myself out from under the dash.

The hot knife worked well with the temperature set to "4" (5 is max). It took about three minutes to carefully make the cuts. One thing to be aware of, and I did not notice this before making the cuts, is the blend door actuator wires are routed through the HVAC box on the right side. You will end up making a cut here and could easily melt the wires. Fortunately with pure dumb luck I managed to avoid damaging the wires. If I did this again I would figure out how to remove the wires prior to cutting.

Prying out the coupon was difficult. At one point I had three flat blade screwdrivers in there. It can be finessed out with careful bending and prying. Once out, I cleaned up the melted plastic on the removed piece and lightly sanded any jagged edges with a foam sanding block.

Next I installed the new blend door in the HVAC box and inserted the nub into the new blend door.

uvraise you were totally right about the inner channel. The removed piece was not going back in easily with this in place. I used a dremel tool with a cylindrical carbide cutter to mill off most of the inner channel, leaving a bit of the top part where it curves. See pics below. With most of the inner channel removed the coupon snapped back in pretty easily. I reinstalled the two 5.5mm screws that hold the HVAC box together then using my hand, verified that that I could actuate the blend door by hand, through it's full range of motion. Note the the range of motion is just shy of 90 degrees. The blend door was left in the heat (down) position.

Next step is sealing it up. Bring plenty of paper towels and goop it up with RTV. This was probably the worse part of the job because it's messy. Just be careful not to get any RTV where it does not belong.

Finally, I just reversed the disassembly process. Reinstalled the actuator, plugged it back in. Plugged in the gas pedal. Shoved the duct back in and loosely installed he lower duct screw to leave some wiggle room. Installed the BCM plastic mounting bracket and rotated in the BCM. Plug in the BCM then tighten the duct screws. Note that when I plugged in one of the BCM plugs I heard the blend door cycle. It sounded like it was working properly. The driver's seat was reinstalled and plugged back in. Reassembly was easy peazy...not really, it was a pain in the ass but doable and by this point my 52 year old body was really aching. Beer therapy fixed this later.

I started the car with the fan off to avoid blowing out the still curing RTV and ran the temperature knob through it's range. The new blend door seems to be working properly without any grinding/plastic destruction sounds. I will give the RTV a full 24 hours to cure and try out the fan/heat/AC this evening but expect everything to be functioning properly.

Here are some pics of what the butchery looks like. This procedure took me four hours but I was taking my time and working carefully. If I had to do it again it would be quicker now that I know what I'm doing. Hopefully I have filled in some more details of this procedure and others will gain the confidence to attempt this repair themselves. I think I'll take some of the $1,300 saved and put some new brakes on the car. I'm growing weary of the warped drilled/slotted aftermarket rotors and shitty ceramic brake pads. Going back to factory stock. Let the wheels turn black in a week, at least it will stop better and the steering wheel vibrations will be gone.

UPDATE: I had the car out and about and everything is working properly. AC is ice cold, heat is blazing hot. I can still smell the RTV but suspect that will go away soon as it has been less than 24 hours since it was applied.

-Ray

[0stones0]

Added to the database.

Heater Blend Door Database

[joekono]

Originally Posted by 0stones0

Added to the database.

Heater Blend Door Database

Thanks 0stones0!!!! Hope I never need it.

[ariZona28]

GREAT descriptive write-up! Tell me where I can pick up one of those cooperative wife units. I keep enquiring at local establishments but I always get the same response: "sorry, temporarily out of stock". I suspect these supply chain issues will not improve anytime soon.

[blumaro]

ariZona28,


They don't come that way when they are new. Lots of training is required. It started the second week after we got married. She stated "Now that we are married I think you should trade in the Trans Am and buy a family car." The Trans Am in question was a 1988 WS6 car with the 5.7 TPI. After some careful thought, I looked at her and stated "I had the car before I had a wife. If someone is going away it's not going to be the car." That ended all talk of trading in the T/A and began the wife unit training. It's been 25 years now and you see what kind of car I drive so the training was successful.



-Ray

[ariZona28]

Yeah, nothing worthwhile is easy. I'm kinda at the point in my life where I've adjusted some of my superficial requirements. Good wrench, good cook, good enough!

[claudiel19]

Im about to attempt this myself in the next week or two. Anything that has to be done to “retrain or cycle” the actuator?

[Danial]

My son-in-law repaired mine thanks to links on this site. Thanks guys!

[Royal Tiger]

Originally Posted by Danial

My son-in-law repaired mine thanks to links on this site. Thanks guys!

Awesome!!!!

I had mine done. I hope it never needs it again.

[camguynj]

Originally Posted by claudiel19

Im about to attempt this myself in the next week or two. Anything that has to be done to “retrain or cycle” the actuator?

Answer is yes. It can be done manually by positioning the Temp dial to agree with the position of the blend door (search thru link on post 62 for examples) or the guaranteed way is to have it recalibrated by a scan tool …see this
https://m.youtube.com/watch?v=GldvTMJE6c0&t=229s