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
http://img70.imageshack.us/img70/1665/img02053uo.th.jpg (http://img70.imageshack.us/my.php?image=img02053uo.jpg)

Picture 2, the blend door taken apart, by removing the 4 small screws
http://img70.imageshack.us/img70/478/img02077ig.th.jpg (http://img70.imageshack.us/my.php?image=img02077ig.jpg)

Picture 3, The Problem, the broken gear.
http://img70.imageshack.us/img70/3673/img02085ec.th.jpg (http://img70.imageshack.us/my.php?image=img02085ec.jpg)

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.

:thumbsup: Good stuff

the reason it breaks is becouse of the material it is made out of, Tephlon is not very durable. I had to replace mine not too long ago, I tried doing the quick fixs and even went to a bone yard to get a used one and that was a flop too, I ended up going to a dealer and spending about 200 bones for it, I checked the numbers and asked why they were different. the dealer called the manufacturer and they said the numbers were different becouse the part was an upgrade, the gear is supposed to be made out of aluminume now. Ive been happpy so far. oh by the way, good post, and if the moderators want they can combine my post on this issue with this one....

Is this the same motor used in the automatic temp control?

Nice write up, thanks.

Is this the same motor used in the automatic temp control?
Yes, this came out of our 98 Blazer that has an automatic temp. control.

KILLER WRITEUP DUDE! WITH PIX!

I've been suffering with this issue for a while. Did you replace the full motor or just the gear?
What small tools you used to get to it? It's VERY difficult to reach the three mounting screws.

http://i16.photobucket.com/albums/b40/JoshB_/relay2.jpg

KILLER WRITEUP DUDE! WITH PIX!

I've been suffering with this issue for a while. Did you replace the full motor or just the gear? And where did you order it from? Cost?
Could you give me the details on the part number for the new motor, and what small tools you used to get to it? It's VERY difficult to reach the three mounting screws.

http://i16.photobucket.com/albums/b40/JoshB_/relay2.jpg

What view is this?

Ok, I just ordered the new blend door motor for the AUTO Climate Control on my 98 Blazer LT. They call the part out as an "ACTUATOR", and it appears as #4 in GM's exploded view.

The new P/N is 89018365

The dealer priced is at approx $180, I got mine from GMPartsDirect.com for:

SUB TOTAL: $97.58
SHIPPING: $21.47
TAX: $0.00
TOTAL WITH TAXES: $ 119.05

Eye level looking through the glove compartment area with the glove compartment flipped open and down out of the way.

I may have to do this, I am having the same issues.

SHIT! I bought my replacement motor, but I'm still having the problem. I have NO movement whatsoever in the motor at this time. Not in the old or new motor. I've checked fuse number 21 in the fuse block on the drivers side dash, and the HVAC fuse under the hood. I'm stumped. What's the problem? Anyone?

Below is the schematic....any help would be GREATLY appreciated. Otherwise I may end up paying the dreaded RIPOFF $90 Diagnostic fee.

http://i16.photobucket.com/albums/b40/JoshB_/98blazer_Page_1.jpg

GM PARTS DIRECT sent me the WRONG DAMN PART! They sent me the actuator for the Manual not the AUTO! No wonder it's not moving, it doesnt have the correct number of pins to receive power!

Auto part:
http://img70.imageshack.us/img70/1665/img02053uo.jpg
-------------------------------------------------------------------
Manual part:
http://i16.photobucket.com/albums/b40/JoshB_/wrongpart.jpg
as you can see it's a different pin setup from the part shown above.
-------------------------------------------------------------------

I called GMPartsDirect, but its all automated. Best you can do is leave a message. I'm so pissed off!

Well, I've been in touch with GMPartsDirect by phone, and they've shipped me the correct part. They admitted to their mistake, and are going out of their way to make up for it. Very promising! The correct part is on the way and should be here today or tomorrow. I will post a HOW TO with photos on the replacement.

If you have a volt/meter and a schematic with a little patience, (which I lack alot off) i am sure you can figure it out. as for the dif pin setups, you got the wrong part, the dealer part will have most of the original part numbers with a few that are diffferent. looks like you got one for a 2000 model. its got to be a R series.

OK, I didnt do a HOW TO with photos or anything, as I didnt have time when I installed the new motor, so I'll just give you a quick FYI on things to keep in mind. Refer to this photo for the following info.

REPLACING THE TEMP ACTUATOR ON A 98 CHEVY BLAZER 4X4

http://i16.photobucket.com/albums/b40/JoshB_/relay2.jpg

1. Disconnect battery cable.
2. Open glove compartment, and lift tab in upper left corner to allow the glovebox to swing down completely towards the passenger floorboard.
3. Gently remove the line that enters the "Vac Unit", and then the "Vac Unit" itself by wiggling it upwards off its mount. Once removed gently swing it towards the drivers side and out of your way.
4. You now have access to the Temp Actuator.
5. Carefully remove the electrical connector that feeds the Actuator.
6. Using a 1/4" drive wratchet, and 7/32" socket, remove the two (2) mounting screws. (HELPFUL HINT: For maximum ammount of clearance, Keep the wratchect handle facing the drivers side when putting it in place.)
7. There is no screw on the back mounting post, just a pin that holds it steady.
8. Once you've removed the screws you may need to gently pry the Actuator up off the blend door with a screwdriver.

Installation is reverse of the Removal. The Blend Door and Actuator are both keyed, so theres only one way to put it in. Guide the Actuator onto the Door, then re-secure the mounting screws.

I created account to thank y'all for this. I realize this is an old thread and I've not looked into it yet, but there is an access panel under hood labeled "Cut here for service" that was mentioned in another thread I had found, for which I do not have a link. I believe that is the easier way to get to that actuator. I'll post back for the archives this weekend.

Thanks again.

The "cut here for service" you are referring to is for blower motor replacement. The blend door actuator is only accessible from under the instrument panel.

Just wanted to add to the thanks on the best information I have found on this subject. I wish I had found this sooner since I dropped my Dash last night to get the motor out. Yep the gear was broken, and Oreilly's autoparts has it for $34.00.
This one thread was worth the time for signing up.

Hey !
My 98 Blazer the actoator moter doesn`t stop . It moves back and forth without anything and in any outher slection ????
Help !!!

I have a 96 S-10 and I was wondering, do I have to take out the entire dash to get to the blend door unit? it seems like the glove compartment is attached to the dash.

http://www.conquestauto.com/servlet/the-1299/New-GM-AC-Actuator/Detail

109.00 free shipping

Billy

How did you get to the 2 screws on top of the blend motor? Is this the same as a 99GMC Jimmy? I dont recognise the pics even though I have all my dash panels off tring to get at this mistery motor. Please help:banghead:
Thank you Dan 612-685-6586

There are two more actuators to the left of the one discussed here. #19 and #17 on dealer print out. I have every bolt I can find out of my dash and still can't move that black plastic piece that is hidding the two acutators. Need help on getting to the actuator.

Hi,
nice witeup in the works.
MY wife's 2000 Envoy has the same problem...blows hot air. A/C lines are cold.
My first suspect was the blend door actuater.
I replaced one on a Ford Windstar and what pita!!@!!!!!!!!!

Do you have more details on the swap/replacement procedure?
Thanks,
jonny

Hi,
nice witeup in the works.
MY wife's 2000 Envoy has the same problem...blows hot air. A/C lines are cold.
My first suspect was the blend door actuater.
I replaced one on a Ford Windstar and what pita!!@!!!!!!!!!

Do you have more details on the swap/replacement procedure?
Thanks,
jonny

Sorry..never got to page 2.
Anyhow..is a 2000 envoy the same?
I guess I'll have to dig into it tomorrow.
Thanks again.

2. Open glove compartment, and lift tab in upper left corner to allow the glovebox to swing down completely towards the passenger floorboard.
3. Gently remove the line that enters the "Vac Unit", and then the "Vac Unit" itself by wiggling it upwards off its mount. Once removed gently swing it towards the drivers side and out of your way.
4. You now have access to the Temp Actuator.
5. Carefully remove the electrical connector that feeds the Actuator.
6. Using a 1/4" drive wratchet, and 7/32" socket, remove the two (2) mounting screws. (HELPFUL HINT: For maximum ammount of clearance, Keep the wratchect handle facing the drivers side when putting it in place.)
7. There is no screw on the back mounting post, just a pin that holds it steady.
8. Once you've removed the screws you may need to gently pry the Actuator up off the blend door with a screwdriver.

Installation is reverse of the Removal. The Blend Door and Actuator are both keyed, so theres only one way to put it in. Guide the Actuator onto the Door, then re-secure the mounting screws.

Thanks!!! Did just that..have part in hand and looks identical to yours..with crack in gear.
O'reilly can't pull up the auto one's price......nor is it available "on-line".

Junkyards or another cheap avenue now.
This was SIMPLE compared to the Windstar I did once!

Thanks for the write up...saved me hours!!