# '04 GMC Dual Climate control heater issue



## Motorman 007

Hi Guys,

My 2004 2500HD with dual climate controls (manual) has an issue. No matter where I put the slide selector, I get full hot heat. Yesterday was 70 degrees and obviously it was extremely noticable. I thought I had noticed something this winter but it was intermittent. I've done some searching but haven't been able to come up with anything concrete yet. I'm assuming it's a blend door or actuator issue. It does it on both sides, passenger and driver. Even with the AC on it full heat. I can't be the only one with this issue so what say you guys???


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## 06Sierra

Sounds like both actauators went out at the same time. The driver side is easy to get to. The pass. side is another story, you have to take the dash apart. Rockauto.com or gmpartsdirect.com have them much cheaper than what the dealer wants. I wasnt' able to find one for my wife's Yukon any where but the dealer, or online.


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## Motorman 007

06Sierra;1269061 said:


> Sounds like both actauators went out at the same time. The driver side is easy to get to. The pass. side is another story, you have to take the dash apart. Rockauto.com or gmpartsdirect.com have them much cheaper than what the dealer wants. I wasnt' able to find one for my wife's Yukon any where but the dealer, or online.


Thanks for the response. I'm kinda trying to figure this out so I've got it apart a little bit. After checking some of the connections and such on the heater plenum in general, I pulled the middle part of the dash out. Undid the two connections to the DZ heater controls. Nothing found, really. Put it back together (you know what's coming next) and it works. GGRRRR. Both zones worked independent of each other as they are supposed to. So I wiggle wires, bang on the heater box, disconnect the main DZ controls like 20 times and can't get it to duplicate the condition again. Reinstall the glove box and the lower cover that covers the resistor area and turn it on. Now left side is all heat, no cool, and right side acts fine. I still have the dash apart at this point.
Here's the kicker. If I unplug the control panel for 30 seconds and plug it back in everything works fine. I haven't seen anything in my research(online) that says the actual control panel and knobs/slides go bad. But I sort of feel like I'm putting it through some sort of reset when I do the unplug/plugin deal. Any thoughts on this info??
Thanks!


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## vegaman04

Common issue, there is a way to calibrate them because they loose there center point. Try calibrating them first, then replace if not successful. 

Turn key on, set one side to full heat, other side to full cool, wait 60 sec, then cycle key off. Repeat last step but reverse it, and then key on for the third time, and test and see if they are working. If not replace.


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## Motorman 007

vegaman04;1269096 said:


> Common issue, there is a way to calibrate them because they loose there center point. Try calibrating them first, then replace if not successful.
> 
> Turn key on, set one side to full heat, other side to full cool, wait 60 sec, then cycle key off. Repeat last step but reverse it, and then key on for the third time, and test and see if they are working. If not replace.


Vegaman04,

Thanks so much. When you say replace do you mean the actuators or the controls?


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## 06Sierra

The actuators, the reset procedure he gave is for the actuators. One of the guys I work with had his pass. side do that. After he messed with it a little, it started working fine and has been since.


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## tuney443

''So I wiggle wires, bang on the heater box,''

That movie with Bruce Willis,with his team of oil drillers who go to the asteroid that's going to destroy the Earth comes to mind whenever I have to start banging on something for it to work.The Russian astronaut pushes aside the hot American astronaut babe after she can't get ignition on the takeoff and starts banging the controls and proclaims something with his accent to the effect ''American,Russian engineering,doesn't matter--when it doesn't work you just have to know how to treat it.'' I love that scene,can't remember the damn name of the movie now.


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## Motorman 007

tuney443;1269136 said:


> ''So I wiggle wires, bang on the heater box,''
> 
> That movie with Bruce Willis,with his team of oil drillers who go to the asteroid that's going to destroy the Earth comes to mind whenever I have to start banging on something for it to work.The Russian astronaut pushes aside the hot American astronaut babe after she can't get ignition on the takeoff and starts banging the controls and proclaims something with his accent to the effect ''American,Russian engineering,doesn't matter--when it doesn't work you just have to know how to treat it.'' I love that scene,can't remember the damn name of the movie now.


That would be Armageddon.


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## Motorman 007

vegaman04;1269096 said:


> Common issue, there is a way to calibrate them because they loose there center point. Try calibrating them first, then replace if not successful.
> 
> Turn key on, set one side to full heat, other side to full cool, wait 60 sec, then cycle key off. Repeat last step but reverse it, and then key on for the third time, and test and see if they are working. If not replace.


Thanks, that seems to have done the trick. Will keep and eye on it and report back if not. Thanks again...Plowsite comes through again.


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## samjr

*i had the samething man*

Did u try to unhook the bat 
B&B told me this unhook your bat for a hr or so i dont know what this does but it worked for me


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## Motorman 007

samjr;1269194 said:


> Did u try to unhook the bat
> B&B told me this unhook your bat for a hr or so i dont know what this does but it worked for me


Since the above only lasted a day I guess I'll try the battery unhook procedure. My gut tells me I'm buying actuators.... RockAuto.com the right place????


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## tuney443

Motorman 007;1269184 said:


> That would be Armageddon.


Bingo.As to your real solution now,sorry I got sidetracked earlier,do disconnect BOTH batteries for about 10 minutes.I had the very same issue,it actually worsens with a plow as the front mounted sensor out by the radiator sends the wrong input to the computer,confusing it.If I want decent heat,sometimes I have to turn each knob to 88-90*.A few times it stayed there until I followed B&B's advice.I doubt very much if you need the actuators.


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## Motorman 007

tuney443;1269628 said:


> Bingo.As to your real solution now,sorry I got sidetracked earlier,do disconnect BOTH batteries for about 10 minutes.I had the very same issue,it actually worsens with a plow as the front mounted sensor out by the radiator sends the wrong input to the computer,confusing it.If I want decent heat,sometimes I have to turn each knob to 88-90*.A few times it stayed there until I followed B&B's advice.I doubt very much if you need the actuators.


Thanks. Mine are the manual slide type(no digital read-out) but I'll try it for sure.


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## Motorman 007

*I'm Baaaaccck....*



Motorman 007;1269821 said:


> Thanks. Mine are the manual slide type(no digital read-out) but I'll try it for sure.


So "none of the above" is the selected resolution. Do I need actuators????


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## 06Sierra

How did the plug for the controls look? No signs of melting around the pins? Are the both still acting up or just one now? When I was having the issues with the yukon I found a different reset procedure. Put both on full cold, pull the hvac fuse and turn the key to run for one minute. Turn the key off and replace fuse. I will see if I can find a little more on that later today.


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## Motorman 007

06Sierra;1277323 said:


> How did the plug for the controls look? No signs of melting around the pins? Are the both still acting up or just one now? When I was having the issues with the yukon I found a different reset procedure. Put both on full cold, pull the hvac fuse and turn the key to run for one minute. Turn the key off and replace fuse. I will see if I can find a little more on that later today.


Just the drivers side is acting up at this point. No burnt connections...all clean contacts. I will say that every time I unplug the connector from the control board, it works fine until I have to adjust the temp. Any more help is appreciated.


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## 06Sierra

I would say it's time for an actuator.


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## Motorman 007

*I'm Back.....*

So we haven't had any Spring weather here until today when it decided to go up to nearly 80 degrees. I haven't replaced the actuators.

I have the dash trim off and the HVAC panel loose. If I unplug the blue plug directly behind the temp sliders and plug it back in, the AC works nice and cool. When driving the vehicle for more than 20 minutes, all of a sudden the drivers side goes full heat and passenger side remains cold. I haven't touched the temp control when this happens. If I unplug the plug it will reset again. Still say actuator or control board???

Thanks


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## 06Sierra

Actuator. That's the same thing my Yukon did.


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## Motorman 007

06Sierra;1281605 said:


> Actuator. That's the same thing my Yukon did.


06,

Appreciate all of the help. Which actuator do I need, the air inlet, temperature, or mode control cam ? Don't want to buy the wrong one(s)


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## 06Sierra

Temperature.


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## Motorman 007

06Sierra;1281739 said:


> Temperature.


Thanks Dude.


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## 06Sierra

No problem.


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## Motorman 007

*Update*



Motorman 007;1269618 said:


> Since the above only lasted a day I guess I'll try the battery unhook procedure. My gut tells me I'm buying actuators.... RockAuto.com the right place????


Bought the Dorman temp actuator from RockAuto.com. It was here in two days and all installed. As others have said, the drivers side temp actuator is a piece of cake to replace. Thanks to all for chiming in with help and opinions.


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## 06Sierra

Glad you got it fixed!


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## samjr

*I just got a recall letter*

Just this week i got a recall letter from GM Basically the recall suggests the interface between the relay and the wiring connector may be incapable of conducting higher current levels when running the blower motor for long periods of time. A short could prevent the fan from operating on certain levels, cause a burning plastic smell in the cabin, and/or the HVAC blower may not turn off even when the truck is turned off! LOL

They advise not idling the vehicle for long periods with the blower motor running, to reduce the risk of fire.

They are trying to obtain enough parts for the fix and will contact me when they are ready for the repair.


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## Eggie329

I had this issue on my Tahoe after I disconnected the battery to replace the alternator. Passenger side fixed itself, but drivers side had to be replaced. Just be sure to do the re-calibration steps after replacing it.


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## Motorman 007

samjr;1283583 said:


> Just this week i got a recall letter from GM Basically the recall suggests the interface between the relay and the wiring connector may be incapable of conducting higher current levels when running the blower motor for long periods of time. A short could prevent the fan from operating on certain levels, cause a burning plastic smell in the cabin, and/or the HVAC blower may not turn off even when the truck is turned off! LOL
> 
> They advise not idling the vehicle for long periods with the blower motor running, to reduce the risk of fire.
> 
> They are trying to obtain enough parts for the fix and will contact me when they are ready for the repair.


That sounds more like the blower motor relay and wiring harness that I have already replaced twice in my truck. You can easily see how a melted connection and or relay could start a fire when you remove it to replace it. The first one was really bad and the NAPA replacement just didn't hold up and burnt out in less than two years. Tell me how I'm not supposed to run the blower for extended periods when I'm plowing....


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