Temperature control not working 99+

[BigDaddyHD]

If your temperature control stays hot even when you turn it all the way to cold, the culprit most likely is the temperature control actuator. This thread tells you how to change it.
Tools required:
1/4" drive ratchet
7 mm socket
5.5 mm socket or 7/32" will work
1 1/2" extension
Parts
GM # 52474810 Actuator Have the dealer double check this. I know this is the correct number for 99 to 02.

Step one
Using the 7mm socket remove the 3 screws holding the passenger side underdash trim panel. The screw above the transmission hump is a pain so be careful and take your time removing it.

Step two
Once the panel is out of the way, the actuator is toward the center of the truck. The electrical plug comes in from the bottom and has 5 wires, unplug it. There are 2 screws holding the actuator in, one on the left and one on the right. Using the 5.5 mm or 7/32" socket, remove the screws. Once the screws are removed, the actuator will come off straight down.

Step three
Once the old unit is off, you'll notice the shaft that the actuator slides on has 2 flats on it. Looking at the new actuator, turn the shaft until it's lined up. Slide the new actuator up onto the shaft, line up the screws and reinstall them. Plug the actuator back in.

Step four (Very important)
Turn the temp control all the way to cold. Pull the HVAC 1 fuse (panel on the drivers side of the dash, top front fuse). Turn the ignition key to run. Leave the key on for at least 1 minute. Turn the key off and put the fuse back in.

Step five
While you have the trim panel off it's a good time to check your cabin air filters (if you have them). About halfway between the transmission hump and the door there is a plate that is about an inch wide, you’ll see a single screw (toward the firewall) holding the cover plate in place. You’ll need a 5.5 mm socket to remove this screw. After the small cover plate is removed, you’ll see one of the filters in the housing. Pull the filter down and out of the housing. You may need to rotate the filter as you pull it down. After the first filter is removed, look inside the housing, and you’ll see the second filter. Just slide it out, pull it down and out of the housing just like the first one.
When reinstalling the new filters, make sure you have the arrow (airflow) on them pointing in the right direction, towards the driver’s side of the truck.

Step six
Reinstall the cover panels and you are done.

Hope this helps out
Big Daddy HD


** added to .tech 6-25-06

[454ss]

Thanks for sharing

[mustang93]

thanks

[burglett]

is there anyway to check this to see if its bad

[PEye]

Good Day All,
I have a '99 Suburban 1500 that has ice cold rear air but only warm air from the front vents. Both controls, dash and overhead (rear) are set to full blue. It doesn't matter whether it is on max or normal the results are the same. I have been compensating by using the max settings to recirculate the air and that seems to push some cold air from the front vents. I did notice that when I only have the front controls set, the compressor clutch actuates intermittently as if the unit was short cycling. When the rear controls are on this does not occur. Freon and system pressure seem to be ok. Any feedback would be helpful. Thanks.

[Superado]

just as a note to a great write up...
ac/delco part # is 1572507 ($36.79 @ RockAuto)

and it seems that Dorman now has a replacement part for it as well...Dorman Part #604101 HVAC Heater Blend Door Actuator($33.89@ RockAuto)

they seem to look identical in form and function...just that the Dorman seems to be made a bit on the cheaper side...

At that price difference, I don't believe that I would buy anything but the ac/delco...

[nimmer]

BigDaddyHD, your explanation for fixing the Temperature Control Actuator is right on the money. The step by step procedure you described worked perfectly for my 01 Sierra. I can't thank you enough for documenting the procedure. When you describe the step about taking the passenger side underdash panel, and the removal of the three screws, you should have emphasized the removal of the screw just above the transmission hump as a little more than a pain, it's a tripple dog dare BI&^CH. Not only getting it off, but getting it back in is horrendous, so my suggestion to anyone doing this job is to follow the steps as described, than have a chilled beverage or two, and than try and get the transmission hump screw back in. My bet is that if you take your vehicle into the Dealer to have it fixed, the technician will probably not even try to get that screw back in. The new actuator works like a charm.

Thank You BigDaddy......

[wayloncle]

Will this work on an 04 Silverado with the controls that control both sides seperatly? My wife's 04 Tahoe started the same thing today the driver side is HOT! passenger side is cold. My truck does it just the opposite.
Thanks

[nimmer]

Wayloncle, I don't know for sure, my vehicle was a 2001 Sierra, but it's worth it to give it a try, on my vehicle it wasn't that bad a job except for the one screw.

[GR8-DANE]

Hey Nimmer, did it work for you?

I've got an O4 with the dual zone and 2 times now I have gotten in the truck and the passenger side only blows hot air while the driver side works fine. Doesn't matter what temps I use, it only blows hot. So far, I have been able to turn it off and on a few times and monkey with it and it eventually corrects itself. But something was preventing the passenger side from blowing anything other than hot. Hate the intermittent problems :)

Thanks!

[jchilling]

Big Daddy and all:

2001 Chevy Tahoe LT with manual climate controls.

I followed the actuator replacement procedure exactly including removing the fuse but the problem is not resolved. I even removed all fuses related to HVAC, A/C or Heater (3 under the hood and 2 in the dash panel).

My on-going problem (post install of new actuator) is this:

I can now turn the heat to about 80% of full and still return to 0% but if I go all the way to full 100% Heat, I cannot return to cold until the truck has been parked (shut off and with temp knob to cold) for a couple of hours +/-.

Internet searches now turn up some things like needing a new BCM (Body control module) or re-calibrating the temp control (which I assume was your reason for pulling the fuse to reset this control module).

Any other suggestions for me before I have to take it to the stealer?

[IceColdtexan]

My 2001 silverado is having the exact same problem. I just replaced the actuator and still staying in full heat. anyone have a fix for this ? Thanks

Originally Posted by jchilling

Big Daddy and all:

2001 Chevy Tahoe LT with manual climate controls.

I followed the actuator replacement procedure exactly including removing the fuse but the problem is not resolved. I even removed all fuses related to HVAC, A/C or Heater (3 under the hood and 2 in the dash panel).

My on-going problem (post install of new actuator) is this:

I can now turn the heat to about 80% of full and still return to 0% but if I go all the way to full 100% Heat, I cannot return to cold until the truck has been parked (shut off and with temp knob to cold) for a couple of hours +/-.

Internet searches now turn up some things like needing a new BCM (Body control module) or re-calibrating the temp control (which I assume was your reason for pulling the fuse to reset this control module).

Any other suggestions for me before I have to take it to the stealer?

[loafycleetus]

there are two actuators....drivers side is on bottom, passenger side is on top under the dash. there are software issues and when the door over travels it locks the actuator, that is why it wont reset untill you cycle power and it relearns the door travel counts....it may freeze in a hot or cold position.

[plowboy77]

Hello gents, I followed the procedure above (very nice write-up BTW) but I hooked up the new actuator and forgot to turn the temp control to the cold side. I hadn't hooked it to the heat/cool door yet so I got to watch the actuator turn around to the 'hot' side and mechanically jam itself in place and not move after returning the control knob back to cold. I had to take the actuator apart to free the gears. Apparently I've got something out of time now because I can't get it to work in the correct range of travel. Everytime it gets to the completly hot side it jams. Any suggestions? Does Rock Auto take returns? lol.
It would appear that the little blue gear inside the actuator is what determines how far the actuator travels. Anyone know where this thing is supposed to be timed?

[whatawa1]

Hello Y'all.
This is an awesome write up. I had the issue of my HVAC only blowing hot air. I have a 2000 GMC Xtended Cab z71. I ordered the part from Rock Auto, and replaced the old actuator per the instructions. I did have a forth screw in the trim towards the driver side that I almost pulled out that needed to be removed. As far as replacing the housing, I recommend replacing the center screw over the hump first as you can flex the trim and line up the screw and then the others are fairly easy.
Thanks again for the post!

[BFaithV]

Thanks for this thread! My 06 Silverado has this problem!

[dajabi]

First off...Thanks BigDaddyHD for the post. It helped me fix my 2000 Z71 4x4 heater control. My main reason for replying is directed to Plowboy77. I too wanted to watch the actuator in action. I did and proceeded to jam it in the far HOT position and had to take it apart to un-jam.
Truth be told, when actually installed and the control is turned to the max HOT position, the heat damper door inside the heater assembly must have a shorter range of travel than the actuator unit will move, therefore it gets tightly closed and stalls out before getting bound up. Hope this helps you.
Dajabi

[Primetime1267]

Would this actuator have anything to due with when the a/c is off, it still blows air (fresh, I guess) on my feet.. It will not close the lower vent, even when I have the system set on recirc...

[ryanthorsen]

Originally Posted by jchilling

Big Daddy and all:

2001 Chevy Tahoe LT with manual climate controls.

I followed the actuator replacement procedure exactly including removing the fuse but the problem is not resolved. I even removed all fuses related to HVAC, A/C or Heater (3 under the hood and 2 in the dash panel).

My on-going problem (post install of new actuator) is this:

I can now turn the heat to about 80% of full and still return to 0% but if I go all the way to full 100% Heat, I cannot return to cold until the truck has been parked (shut off and with temp knob to cold) for a couple of hours +/-.

Internet searches now turn up some things like needing a new BCM (Body control module) or re-calibrating the temp control (which I assume was your reason for pulling the fuse to reset this control module).

Any other suggestions for me before I have to take it to the stealer?

my damn truck has the same problem except it does it on cold or hot. id say 25 percent of the time it doesnt do it but the other 75 percent its stuck on hot or cold. what the hell is the problem?

[cookie123]

Did you ever get your actuator installed? I can't line mine up with the door post either.