Need Some help after replacing actuator. Now no HEAT?! what!?

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Emily Smith

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Hello, I have searched for my specific problem and haven't found any insights, so I'm sorry if this has been covered somewhere and I missed it.
I have a 2004 GMC Yukon Denali xl 1500 with the 6.0l engine. I have automatic dual thermostat controls. I was having hot air blow from the drivers side only after a couple seconds of being on ac. I did the relearn listed here, it didn't fix the issue so I replaced the actuator with a dorman 604-111. Violia! Cold continuous ac air on both sides of the vehicle! Yay. For thoroughness, I checked the heat.... Not hot on the drivers side. Gets very hot on the pass side, just ambient temp air on the drivers side. I checked the coolant, and did the relearn process to the new actuator with no better results. I'm lost. I checked the rpo codes on my part to what's listed in the glove box, everything appears to be right... Does anyone have any further ideas or instructions? If it is important I had the radiator replaced about a month ago, I haven't tested the actual heat since then, but the air that came out of the drivers side when the actuator was bad, was definitely heat then, definitely hotter than ambient temperature.
 

Fless

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What's your coolant temp gauge reading?

Not saying this is it, but there have been issues with aftermarket radiators that don't have the proper restriction in the connection going back to the surge tank. They don't allow the engine to reach operating temp.
 

swathdiver

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Hello, I have searched for my specific problem and haven't found any insights, so I'm sorry if this has been covered somewhere and I missed it.
I have a 2004 GMC Yukon Denali xl 1500 with the 6.0l engine. I have automatic dual thermostat controls. I was having hot air blow from the drivers side only after a couple seconds of being on ac. I did the relearn listed here, it didn't fix the issue so I replaced the actuator with a dorman 604-111. Violia! Cold continuous ac air on both sides of the vehicle! Yay. For thoroughness, I checked the heat.... Not hot on the drivers side. Gets very hot on the pass side, just ambient temp air on the drivers side. I checked the coolant, and did the relearn process to the new actuator with no better results. I'm lost. I checked the rpo codes on my part to what's listed in the glove box, everything appears to be right... Does anyone have any further ideas or instructions? If it is important I had the radiator replaced about a month ago, I haven't tested the actual heat since then, but the air that came out of the drivers side when the actuator was bad, was definitely heat then, definitely hotter than ambient temperature.

With a bi-directional scan tool, you can see how the four actuators are doing in there and if any have failed and why. You can also use the tool to command them into position and do a proper relearn. Who do you know with a Tech-2? Live near me by chance?
 

treehan77

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Try the re learn procedure again. Basically, turn all heater/ac controls to defat or off etc, disconnect t battery for 15 minutes. Reconnect. Start truck, don't touch anything for 5 minutes, turn off. Done

 
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