HVAC Working Intermittently

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Markguarino

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2014
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I have a 2014 ram 1500 Sport with dual zone climate. Last winter I was having a problem with the heat changing gradually over to cool whenever I would drive for a half hour or more and I'd have to bump the temp up to get any heat. Next time I started the truck the heat worked fine unless I'd drive for a half hour or so or more. I ended up flushing out the coolant, changing the thermostat and putting fresh coolant it. Didn't really make any difference.

This year after talking to a few people I changed the blend door actuator for the left side but it still isn't functioning properly. So I got a new HVAC control module which hasn't made any difference.

Whats happening now it I can't always control the air flow and which vents it comes out and I still can't control the left side temperature. If I unplug the hvac control module I can at least get the defrost to blow so I can drive in the morning. It seems that every time I change a part or unplug something and plug it back in almost everything works until i shut my truck off and turn it back on. Then its back to not being able to control anything. Any ideas what might be the root of these problems? Is it possible that if one of the hvac actuators is bad it affects another one? I think the problem actuators are the left temp actuator, the face/defrost, and the foot. None of them are working as they should which led me to believe it might be the control module but after installing a couple new ones I got the same results which were the rear defrost light flashing which means theres an hvac problem and it wouldn't work at all.
 

SitKneelBend

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I have a 2014 ram 1500 Sport with dual zone climate. Last winter I was having a problem with the heat changing gradually over to cool whenever I would drive for a half hour or more and I'd have to bump the temp up to get any heat. Next time I started the truck the heat worked fine unless I'd drive for a half hour or so or more. I ended up flushing out the coolant, changing the thermostat and putting fresh coolant it. Didn't really make any difference.

This year after talking to a few people I changed the blend door actuator for the left side but it still isn't functioning properly. So I got a new HVAC control module which hasn't made any difference.

Whats happening now it I can't always control the air flow and which vents it comes out and I still can't control the left side temperature. If I unplug the hvac control module I can at least get the defrost to blow so I can drive in the morning. It seems that every time I change a part or unplug something and plug it back in almost everything works until i shut my truck off and turn it back on. Then its back to not being able to control anything. Any ideas what might be the root of these problems? Is it possible that if one of the hvac actuators is bad it affects another one? I think the problem actuators are the left temp actuator, the face/defrost, and the foot. None of them are working as they should which led me to believe it might be the control module but after installing a couple new ones I got the same results which were the rear defrost light flashing which means theres an hvac problem and it wouldn't work at all.
Interesting, when you shut off the truck can you here the HVAC system recalibrating all of the doors or is it silence (you should here servos after the key is out).
 
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Markguarino

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Interesting, when you shut off the truck can you here the HVAC system recalibrating all of the doors or is it silence (you should here servos after the key is out).
Yes I’ve always heard them recalibrate and I still do
 
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Markguarino

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Yes I’ve always heard them recalibrate and I still do
I’m wondering if my left temp blend door is broken or messed up somehow because there’s a little tension when I manually rotate it from behind the glove box. It doesn’t fall to cold and will stay up at hot unless I turn it to cold, which might be burning out the actuators I’ve put in.
 

SitKneelBend

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Yes I’ve always heard them recalibrate and I still do
I was thinking maybe if it wasn't calibrated properly that it's possible that may be the issue. I think there are some procedures you can initiate with AlfaOBD if you have the app.
 
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