Blend Door (with pictures and the common problem)

[newblazerowner]

Im having trouble getting the part out of the area just with glove box open. No other obstructing objects in the way I should remove? thanks Josh Barber, riccbhard and muzzy1maniac and thread has been great help!

[keith1964]

I have the same problem with my 2000 chevy blazer.replaced waterpump,radiator,heater core, thermostat, hoses and belts and still am freezing my butt off.great heat before you turn on blower fan then poof gone,zip,nada,nothing. i just ordererd this partand i am eagerly waiting to see if this is the problem.if not the blazer goes to the nearest dealership and gets traded in for a nice toyota highlander. these midwest winters get really darn cold. i want to be able to feel my hands and toes again.. thanks for all the great tips.if this is it i will be very happy.

[viggy58]

sounds like your problem is an air bubble, or climate control issue.

post a new thread in the "problem diagnosis" section for some feedback...

[keith1964]

i have been burping this thing for almost a year any air bubble should have been gone by now wouldn't you think? this has been one of the worst vehicle i've had next to my dodge caravan. nothing has worked right since buying this thing. if i get heat i'll be less grumpier.but will still trade her in. but everyone who helped with pictures and suggestions i thank you very much.

[WonderWrench3]

I spent alot of time looking for this thread about a year ago and thought I bookmarked it but now after ? much time I found it again.
What I wanted to provide was the heater/parts schematic. Hope it posts correctly.
http://www.compnine.com/index.php?u=...08&grouptype=B

[searnhardt]

I have a '94 S-10 and have changed out the Blend Door actuator 2 times in less than a year. This last time, I had a battery that was down a cell so I thought that may have contributed to the quick failure. However, I have now had the SECOND replacement die. I was even taking care to leave about 3 clicks of the knob on the hot and cool in case it was getting "rammed" into the sides. I've got the dash removal down and could probably have the bad actuator out and the new one in in just a few hours. However, even though I'm pretty good at it, I do NOT like doing it every 3 months! Given that the controller in the dash is a simple potentiometer, could there be something wrong with it? Does anyone know what the readings on the pot should be? I'm wanting to say that I was seeing 0 volts one way and 12 volts the other; but I won't swear to it. I've found the switch at RockAuto and a few other places online, but I'd like some sort of "good feeling" that it will solve my problem before I tear the dash out again. Advice? Links? Thanks!

[quadap]

Hi All-

I am happy to see this post exists. I have had ongoing issues with my heat/cool control in my truck since a year after I bought it. It started when I took it in for the Window wiper recall. Since then, it has not worked right. I took it back and they said it wasnt anything that they did.. That was 2003....

I have a 1997 2DR 4x4 Blazer w/ 4.3 with manual temp control.

The problem is that it blows heat only. I can get it to go to cold, but only a certain way. The only way I can get it to blow cold air is to have the truck running, put the truck in park and have the blower motor on low. When those conditions exist, I can slowly turn the temp knob from hot to cold. Pending I do not touch the temp knob, it will stay cold. If I touch the temp knob at all, the blend door (I assume) slams shut (which I can hear) and then it blows Hot as Hell air.

after reading all of the posts on this topic, I am still highly confused as to the 'fix' for my issue.

If anyone can help, please do.

[Alternatorman]

The blend door on my 2001 GMC Jimmy has an inspection cover with three screws in it under the hood .
Here is a picture of the inspection cover, thke this off and you can see if your blend door is working.

http://s1197.photobucket.com/albums/...alternatorman/

[old_master]

Originally Posted by Alternatorman

The blend door on my 2001 GMC Jimmy has an inspection cover with three screws in it under the hood .
Here is a picture of the inspection cover, take this off and you can see if your blend door is working.

http://s1197.photobucket.com/albums/...alternatorman/

Just an FYI: On vehicles equipped with Automatic Temperature Control, the cover is held on with 3 screws. On vehicles with manual HVAC, the evaporator housing must be cut and the heater blower resistor removed to see the blend door.

[tdoshi9]

ok so i seem to be having the same problem kinda. my system was low on 134a so i topped it off. not the compressor stays on like it should. it will blow cold air for about 3 seconds then switch to head for 4 or 5 sec. it repeats no mater what setting i have it on. i have a 99 envoy. i don't know history of this vehicle as i just bought it this way. any thoughts? blend door swiging? no noises or anything. im lost!

99 envoy
has auto climate!
clutch not slipping.
compressor is working!
right pressures on system!

i realize this is old but i only have seen this thread as being what i am going through and need a bit more help!

[TurboMitch]

I know this thread is old, but it has been a HUGE help. I stumbled across this thread after having dealt with the inability to adjust the temperature on my heat/AC for a year and a half. I was told 2 months after I bought it that it was the blend door and it would cost over $500 to fix because they'd have to remove the dash.

Thanks to this post, I now have pulled the actuator and have confirmed the gear was broken. I purchased a new motor and plugged it in before attaching it and there is no movement in the motor. I checked all fuses and they are all fine.

Any ideas as to why the problem might be?

As a temporary fix I used a small pair of vice grips to hold the door to the cool position. I also recharged the A/C but it doesn't seem to be getting cold. Any ideas for this too?

[Ktjokt]

So incredibly glad that I found this thread! It is currently 98 degrees outside and the heat was stuck on in our 98 Chevy Blazer with climate control. Even when the unit is turned off, it still blows hot air out through the vents. Found this thread, followed the simple step by step directions to get it out and sure enough-- the plastic gears inside the actuator box were broke in half! Hubby is on his way to the parts store to get a replacement. $140 but it sure beats the $600 that it would cost to have a mechanic do it! Thanks so much for posting the cause of my problem along with the instructions to fix it.

[prudence12]

Originally Posted by riccbhard

A common problem is to find one day when moving the climate control knob on your 98 Blazer to the cold position and tap the A/C button you get still hot air and hear a *creak* *pop* from under the dash. So now what? Well, chances are it's the blend door motor, the unit that moves a blending door in a duct behind the dash on the passenger side that moves anywhere between cold and hot, corresponding with your temperature knob.

We were able to get the one in our 98 Blazer out by dropping open the glovebox and using some small tools.

Pictures:

Picture 1, the electronic blend door motor


Picture 2, the blend door taken apart, by removing the 4 small screws


Picture 3, The Problem, the broken gear.


Why the gear breaks I am not sure. The door itself does not seem hard to move.

More to come later, such as pictures of where it is located.

Currently, the blend door itself in the Blazer is tied to the cool position so the A/C works.

Great job!!!

[Banksno925]

Hi guys,
I have had a lot of problems with my 200 envoy heat a/c. I have gotten it to the point where it now works but the blend door motor constantly cycles. So if I put on a/c it blows Hot air then cold air constantly switching every 30 seconds. So I tried to unplug the blend door motor to get it to stop on one position hot or cold. It worked I stopped it on a/c and now get cold air. So I don't know if it just needs to be realigned I did take it out and put it back in. Any idea's ?

Problem 2. While getting to the blend door for the 5th time. When I unplugged the vaccume thing that controls my vents I snapped the end of the plastic arm off. Its a plastic arm that controls my vent routes. When u 1st drop glove box and have to unplug and move the vaccume to get to blend door. Well the hook that connect the vaccume to the vent controle snapped. Now what ? I mean it makes me not even want my truck because of this dumb problem ? How would I even go about getting that arm ? and how would I replace it ? I don't think glue would hold it because the part that snapped is constantly pulled on to redirect vents. I don't know what to do any suggestions ? Thanks for your time I know its probably hard to read all this.

[jeftex]

A year now I have fought this issue. Lack of funds and just maintaining a job. -It happened on a trip last January, snow ice, only needed heat. After looking at the actuator motor and the position it is in. I could not see how any tool could be put into that tight spot. Anyway my cheap solution involved bypassing the heater coil.. I could see that the compressor was producing condensation. As summer was quickly heating up I at least had cold a$$ air. While scoping out the original issue, I looked at the actuator in action (Manual temp control red/blue) It moved back and forth. The issue is the blend door itself. I have heard it can get weak. Would not completely close off the hot air. The hot will over power the cold. My summer fix worked, now I have to get ready for the winter again.