How to fix Hot Air when A/C is on. Install new air mix/blend door actuator

[jesse13]

After having my battery unplugged for about a week the blend doors would not switch from defrost to vent. I used the relearn method that op posted and BOOOMMM!!! It fixed the problem. Thanks OP

 

[SLCHOE]

You need to find out which one it is. You need to test out each door.

Temperature Blend door: Does the air switch from cold to hot?
Floor/Vent door: Can you switch from windshield to vents to floor?
Recirculation door: If the above two are working properly, this is probably the culprit. This door switches from directing cabin air or fresh outside air into the blower intake. While switching you should be able to hear a difference in air volume as it changes.

Well I finally installed the Blend door actuator from Dorman. And it was a pretty simple straight forward. Did the calibration after installation and now the A/C and heater function works again like it used to. Thx TYF members for all your help!

Hi All
Changed The blend door actuator. under the Glove Compartment Still blowing heat out
Of the passenger side. Now after reading for several hours I have found out I changed the Drivers side actuator. I guess it is OK as the drivers side acts up rarely but does act up.
Other problems noted and learned.
1 The rear unit now only blows cold. Looks like the rear AC controller mounted on the
rear Blower case is the problem. one with the Red / Gray connectors
2 The front AC control head "when it is cold out" when you set the temp from cool to
warmer the temp readout will go up one or two degrees and then down a few degrees
when it warms up works correctly most of the time.

All in all I really like the truck the manacles have been great But the Electrons SUCK lately.
The truck is coming up on 190 thousand miles other then service work it has been good.
Some of the repairs I have done
Had Coolant leak at water pump " Bad Gasket " changed gasket, thermostat, water pump
and all hoses $$$ While we were in this deep Replaced Bad "wet" Knock sensors When all
back together would not turn over. Replaced Starter. Started right up. This was all at 180k
Factory Brakes went 175K still had some pad left.
Changed Alternator 150K
Rebuilt Dash Gage Cluster 145K
Last Week end The Tailgate window Hinge came louse from the Glass Can not be re-glued
will need a new window !@@## $$$
All in all it is still cheeper then a car note. I have learned a lot from these forums but all the answers are not correct. So read read and read some more. You will get the correct answer
if you keep looking.
Also THANK You to all that try to help each other together we can fix most things
Michael

1) rear HVAC module

2) The main control head is bad. Mine does the same thing but I live with it until I can find one out of a parts truck for free. The pots in them are crap and fail. I have to push on the knobs for mine while I turn them to get the to work and even now that's starting to not work. I know what it is but I'll deal with it. Up here in Utah, you have 2 HVAC settings. In the summer, super cold. In the winter, super hot.

 

[regguay]

I was having same issue with our Yukon on and off for past few years until finally was blowing only cold air at the rear during the winter then had to fix it. Another post showed that the actuator could be taken apart and repaired and that is what I did. There is a metal contact inside with little brush like contacts and it seems they get contaminated with grease over time which is used to lube the gears inside and must break the ability to conduct current. I just bent the little metal brushes back a little to make sure they are making contact, cleaned the electrical contact surface where they contact together and worked fine ever since. did same to the front actuator door because it was acting up sometimes. Just mark the actuator and the housing location with a marker before taking apart the actuator assembly so you put it back together the same or you will have problems lining up the actuator with the heater door knob that it has to align up with. Easy fix.

 

[STL_Denali]

I had an issue with the Rear vents only blowing cold last November. Replaced the Control Module (15-73506 ) and fixed the issue. Now yesterday turning on the Rear AC (after its been working all summer) its blowing hot. Hard to tell if its heater hot or just hot since its 100 degrees out. I wouldn’t think the control module would go bad after 8 months or so….

 

[mallarddede]

I have a similar problem...front A/C works GREAT...but only hot air to the rear. Both Rear Actuators are working properly as I visually tested them without interior panel on. I am NOT getting cold air to the rear at all....any ideas? My vehicle is a 2000 GMC Yukon

 

[Greg W]

I have an '05 Yukon Denali with dual climate control. Recently replaced the driver side blend door actuator and fixed the driver side hot air problem. Now the HVAC on both sides blows cold when set all the way to 89. At 90 they both transition to hot. Go back to 89 and both sides transition to cold. This happens whether outside temp is 70F or 105F. If I set both sides to 89 then move one side to 90, that side blows hot and the other side stays cold. Works same way either side. In auto mode it's blowing out the dash vents, but I can also switch between floor, dash and defrost vents and the same thing happens - 89 blows cold, 90 blows hot. I tried an Autozone remanufactured climate controller but everything still acted the same. I've gone through the reprogram procedure a bunch of times.

Suggestions?

 

[heater_up_c]

I have an '05 Yukon Denali with dual climate control. Recently replaced the driver side blend door actuator and fixed the driver side hot air problem. Now the HVAC on both sides blows cold when set all the way to 89. At 90 they both transition to hot. Go back to 89 and both sides transition to cold. This happens whether outside temp is 70F or 105F. If I set both sides to 89 then move one side to 90, that side blows hot and the other side stays cold. Works same way either side. In auto mode it's blowing out the dash vents, but I can also switch between floor, dash and defrost vents and the same thing happens - 89 blows cold, 90 blows hot. I tried an Autozone remanufactured climate controller but everything still acted the same. I've gone through the reprogram procedure a bunch of times.

Suggestions?

Had this problem myself. Previous owner cut the wires to the Cabin Air Temperature Sensor Aspirator. It is right above the driver seat looks like it might be a little speaker or mic for on star. Once I reattached the wires and started the truck, the sensor was making a pretty annoying buzzing sound. Replaced sensor now I have temp control again. Hope this helps.

 

[vjr021]

This sounds crazy, but it works... a temporary fix for this is to turn the truck off and cycle the ignition three times... when you restart it, the system will reset and it will work fine (until it does it again)... I do it about once a week...

 

[jough]

My driver side actuator switches from AC to heat randomly. However, just restarting it resets the actuator. I don't need to cycle the key 3x on my 2004.

 

[darth_burban]

Hey guys I got a 2000 suburban, I have lukewarm heat on the hot setting. I attempted recalibration and that failed. I took a look at the actuator and found it wasn't plugged in. Plugged it in, same ill effect. Heater hoses are getting warm, radiator hoses as well. Truck stays at 198-200*. Truck has a fresh head gasket, with green universal coolant. I flushed the old coolant out, which was green as well... Is it heater core? Rear heat is the same way...

 

[heater_up_c]

Hey guys I got a 2000 suburban, I have lukewarm heat on the hot setting. I attempted recalibration and that failed. I took a look at the actuator and found it wasn't plugged in. Plugged it in, same ill effect. Heater hoses are getting warm, radiator hoses as well. Truck stays at 198-200*. Truck has a fresh head gasket, with green universal coolant. I flushed the old coolant out, which was green as well... Is it heater core? Rear heat is the same way...

Did you burp or bleed the air our heater core?

This is just a helpful tool it is not required. A Radiator Coolant Vacuum Refill Kit sure does help the process. They work like a champ, plus you can also tell if you leaks. It will suck down the hoses flat and put a vacuum on the water cooling system. Then you flip a valve and the vacuum in the system pulls the fluid from a bucket or what have you back into the cooling system.

 

[darth_burban]

How do I do that or is there a step by step thing?

 

[iLikeEggs]

Thanks for sharing this! I h h feeling that I will be tackling this before long. Sometimes in order for my cold air to fully come through I have to turn the temp to high for a few seconds first. Lol.

 

[heater_up_c]

How do I do that or is there a step by step thing?

Check out youtube for your vehicle, there are many videos there to check out.

 

[heater_up_c]

Thanks for sharing this! I h h feeling that I will be tackling this before long. Sometimes in order for my cold air to fully come through I have to turn the temp to high for a few seconds first. Lol.

May want to check out your temp blend door and/or actuator.

 

[vjr021]

Quick fix for this: Turn truck off then on three times, it clears the computer and resets the actuator - temp fix, sometimes good for weeks, sometimes days.

 

[04tahoe229]

Is the actuator only for hot and cold? My tahoe will only work blowing out of dash vents. I can turn knob for defrost of feet but it doesnt change. Also my drivers side blows harder than passenger side.

 

[Jukon]

I have been having a problem of Hot Air blowing out of the passenger front vents when the A/C is turned on. If I would switch to the heat setting, and then go back to cold setting, heat would still blow out of the vents even tho I could hear compressor working. Have had this problem for a year now, and asked on this forum but nobody new the answer, n some people had same problem, so thought I would help anybody out who may have this problem.

Well I flushed my radiator today and had to turn the heat on high to flush and fill radiator. When I turned the switch back to cold and turned A/C on, still hot air was blowing out of vents. It is way too hot in Arizona to not have Airconditioning!!! So I finally figured out what was the problem and here it is.

It is a faulty Air Mix actuator or Blend door actuator.

It is located on the passenger side floor board under the dash.If you have the hush panel it will need to be removed using 7mm socket.

Next you will disconnect the wiring harness and remove the two 5.5mm screw heads.

After both screw are removed, the rear one is alittle difficult to get to so I just used the socket itself. The actuator itself should just pull right down, may be alittle tricky if fully in stop position.

I purchased a new actuator, and just reinstalled back into vehicle. You will want to make sure the door is positioned the same as the actuator by moving the arm in the vehicle, NOT THE ACTUATOR. DON'T ADJUST ACTUATOR ITSELF, LEAVE THE WAY YOU PURCHASED. Mine was set in the cold.

If you buy a new actuator, you need to make sure the part numbers match because they make many different styles of of these actuators for different vehicles and climate controls. Mine may differ from yours so don't base my part number on what you need to buy.

Now here is the tricky part that I had to research. Thanks to a site called Sparky's Answers, I was able to figure this all out and pass it onto everyone here. Very good information recieved, and very thurough. So I am going to use some of his information so everyone will be informed correctly.

Now supposedly if you have a scan tool you can adjust and calibrate the actuator thru the scan tool. Since I don't, he also gave information on how to calibrate without a scan tool. So here ya go.

First once you get actuator, new or used, make sure it can not move( I mean the metal know shouldn't be able to move by hand and diffenently don't move with pliers), if so, it is probably bad, if not go ahead and install the way it comes, and reconnect wiring. Then you will disconnect the battery for atleast 30 seconds. Then reconnect battery, turn the ignition to the ON position for atleast 1 minute, but he suggested 3-4 minutes so that's what I did, and DO NOT TOUCH THE A/C CONTROLS!!! You will then turn ignition to the OFF position for atleast 10 seconds, then start the engine and confirm the new actuator is working correctly by turning the climate knob from cold to hot. If all was done correctly it will work!! I checked the actuator by being on the passenger side, turning ignition on, moving climate knob, and sticking my head under dash to watch for the actuator to move.

SUCCESS!!! Hope this write up helps anybody with this same problem. Any questions please feel free to ask, and I will do my best to help. If I missed anything, or miss typed, very sorry, my kid is trying to help write this!! LOL

Thanks a LOT for this post. This fixed my AC problem! I knew my compressor was spinning, my low pressure AC line was freezing cold, the blower was on, and yet no cold air. I swapped this out and bam, cold air. Thanks again.

 

[metelhead]

Thanks a LOT for this post. This fixed my AC problem! I knew my compressor was spinning, my low pressure AC line was freezing cold, the blower was on, and yet no cold air. I swapped this out and bam, cold air. Thanks again.

I'm having the same problem, but its the driver's side that blows hot when the passenger blows cold....fresh charge on the AC. I can get ithe drivers side to work temp if I cycle the heat/cold adjustments on each side.

Where can I find a schematic for the actuators, to find out which one operates which function?

 

[Jukon]

I'm having the same problem, but its the driver's side that blows hot when the passenger blows cold....fresh charge on the AC. I can get ithe drivers side to work temp if I cycle the heat/cold adjustments on each side.

Where can I find a schematic for the actuators, to find out which one operates which function?

Watch this: