HVAC Blend door Actuator replacement?

Tiny
JOE THE MARINE
  • MEMBER
  • 2002 CHEVROLET BLAZER
  • 4.3L
  • V6
  • 4WD
  • AUTOMATIC
  • 191,000 MILES
I need to replace my HVAC actuator inside the glove box. When I unplug it, I see this has a 4-pin wire plug, all the new ones I want to order have the pins moew pins where it gets plugged in at, does it make any difference if I buy one that has extra pins? The one I have has numbers, left to right 10 9 8 7 6 is blank and 5 is blank. I see Dorman has part number 604-100and 604- 101 different price but have more pins. I was confused in this issue, with the pins and was just wondering, will the aftermarket ones still work, and what do the extra pins mean? Mine is a manual dial, changing the cold scale to hot. I hope I didn't confuse you on this issue, I just do not want to put the wrong one in, because I know this is not going to be fun doing, especially with bruised right hand and knuckles. Any help will be thankful. God bless you on the work you do. One last thing, do they have to be calibrated so how after its installed? I watch too many YouTube and I am really dump founded.
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Friday, February 9th, 2024 AT 3:17 PM

15 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

I'm not sure you are looking at the same part. I attached a connector image of the air temperature door actuator below. Let me know if it is what you have.

Next, to replace this actuator, the manual indicates the instrument panel carrier needs to be removed. This is somewhat of a nightmare. LOL

So, pic 1 below shows the connector. Pics 2 - 9 are the directions for replacing the actuator once the carrier is removed. I added pic 10 for recalibrating the actuator, but the manual only indicates this needs done with automatic climate control.

The remaining pics, starting with pic 11, are the directions for Replacing the IP carrier. You aren't replacing it but that is how the removal directions are provided. Also, (and this is from memory only) I don't believe the IP carrier needs to be fully removed. If I recall, once the upper and lower carrier bolts are removed, you can roll the IP enough to replace the actuator. Just be careful to avoid wiring damage.

Also, back to your original question. You need to make sure the connector will even work with yours. Often, connector pins are not all used. Your vehicle, for example, has a six pin connector, but only three of the pins are used. What I recommend is to deal locally. Remove the actuator to see which you have. I have a few reasons I'm suggesting this. First, there are several different part numbers which appear to work. That indicates there were different designs based on model, package, and climate controls in the vehicle. Second, I have seen so many aftermarket parts failing. You don't want to go through the return procedure if needed. Finally, and to me most importantly, you don't want to do this job twice.

I hope this helps. Let me know if you have questions.

Take care,

Joe

See pics below.
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Friday, February 9th, 2024 AT 11:02 PM
Tiny
JOE THE MARINE
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Will do as instructed. After I install i, do I have to calibrate it or does it do it by itself?
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Sunday, February 11th, 2024 AT 9:57 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 107,716 POSTS
The only thing indicated in my manual is related to an automatic climate control system. Nothing is listed for manual climate control.

However, if there are any issues, it won't hurt to try the reset for the automatic type so I attached the directions below.

Let me know if this helps or if you have other questions.

Take care,

Joe

See pic below.
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Sunday, February 11th, 2024 AT 2:59 PM
Tiny
JOE THE MARINE
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Thanks for the feedback. Is there anyway I can check and found out if any of the pelham doors are working ok, and the flow of air is working okay, I have this gut feeling that one of the doors isnt getting enought air to the floor and more to the top vents.
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Tuesday, February 13th, 2024 AT 4:12 AM
Tiny
JOE THE MARINE
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  • 62 POSTS
I do not want to be a pain, just wanted to ease my mind since I did the new blend door actuator.
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Tuesday, February 13th, 2024 AT 4:13 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 107,716 POSTS
Hi,

As far as testing airflow direction, that is controlled by the mode door actuator. You should be able to hear that more or change the airflow direction.

Also, if I recall, the mode door actuator is actuated by an engine vacuum supply. Did you notice any vacuum hoses under the dash? See pic below.

Let me know.

Joe

See pic below.
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Tuesday, February 13th, 2024 AT 2:26 PM
Tiny
JOE THE MARINE
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I did and replace all the hoses under the hood and vacuum all the lines inside the dash to make sure they were all clear, since there was transmission fluid in some and made sure they were all clear with a vacuum tester. It seems that is it possible the doors that open are not completely open? I'm guessing on this, since I installed the new blend door part and prior to that I was only getting air to the top vents, full blast and now, it is even open to the floor and vents and defrost. Maybe it's a mine changer on me. Is there any way I can find out if the doors are fully open on all the heater pelham. Just a thought. Curiosity on my part. I guess I better stop watching all those videos on YouTube showing it could be this or that, that drives you crazy. So far, you be a great help, God bless.
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Tuesday, February 13th, 2024 AT 4:52 PM
Tiny
JACOBANDNICKOLAS
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Joe,

These kinds of things can drive anyone crazy. LOL If you do have a vacuum pump, run a vacuum hose to the vacuum actuators and apply a vacuum to see if you get a different result. Try that and see if makes a difference.

Let me know.

Joe
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Tuesday, February 13th, 2024 AT 5:48 PM
Tiny
JOE THE MARINE
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Another question? I also have a 2000 Blazer, 4 door, I went inside the glove box to see how the heat, vents and defrost work. I see that when I switch to floor or vent or defrost. The door that opens for the fan is closed, and the heat really blows on the floor and the others. But when I turn the selector to A/C, the fan door opens up and really blows the a/c air, which is ok. This is the problem with my 2002 blazer. I did a check on this in the glove box and when I have the temp. On hot, the fan door open, which it shouldnt and all the other dials. Could this be a vacuum line under the hood crossed? I already change the blend door actiador on the 2002 and was wondering it this the problem? Also, , I disconnect the vacuum that opens the fan door just to see if I would get better and more air for the vent and floor but nothing change. This is driving me crazy and its cold outside, need better blowing of the heat on the floor. Im lost on this issue, tks
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Wednesday, February 14th, 2024 AT 10:44 AM
Tiny
JACOBANDNICKOLAS
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Hi,

Were you able to test the vacuum actuator? As far as disconnecting the vac hose, I'm not sure that would change the pressure. If you move it manually, does that affect the air flow?

Joe
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Wednesday, February 14th, 2024 AT 7:58 PM
Tiny
JOE THE MARINE
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Is that the one which controls the door for the fan door to open? If it is, when I do unplug the vacuum, the fan door closes and nothing changes on the floor vent or the top vent or the defrost vent. Im ging to start from scrach by changing the blender door actuator, then see what happens. Will keep you posted. Also, will get a new dash control unit and see if this could be the problem, what do you think? I'm open to all ideas.
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Thursday, February 15th, 2024 AT 10:37 AM
Tiny
JACOBANDNICKOLAS
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Hi,

Take a look at the pic below. Is this the door/actuator you are referring to? If so, that is the fresh air/recirculation door and actuator. That won't change the air flow volume.

Let me know.

Joe

See pic below.
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Thursday, February 15th, 2024 AT 7:39 PM
Tiny
JOE THE MARINE
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That's the one I was talking about. Will be testing it today, and get back to you on the results.
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Friday, February 16th, 2024 AT 8:11 AM
Tiny
JOE THE MARINE
  • MEMBER
  • 62 POSTS
Okay, back. I installed a different HVAC inside and the fan door closes. That solved that problem of the fan door always bing open and sounding like a jet inside the blazer. Now, next question, it is blowing warm air not hot, even when I drive, just warm air. I was going to change the blower motor resistor, since I installed a new one, maybe this will get hotter. Im still having the vent air flow not doing its job, also I have the new blend door actitor installed. All vacuum lines are new acheate climate control panel switch in today since the one I got at the junk yard seems like it's not working right, will see on this issue. I still believe that its one of the doors not opening in the heater box and thats why I not getting enought heat or the vents are not working as they should. What do you you think? Your call.
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Wednesday, February 21st, 2024 AT 5:38 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

Is the engine reaching operating temp? Do me a favor. Allow the engine to run with the heater on until the engine reaches operating temperature. Turn the engine off and feel both heater core hoses. The supply line should be a little hotter than the return, but both of them should be hot.

Let me know.

Joe
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Wednesday, February 21st, 2024 AT 6:46 PM

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