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Discussion Starter #1
For those of you with automatic temp control that heats the cabin, then blows cold, requiring you to crank it up to 80+ just to stay reasonably warm, I've done a simple, cheap mod that seems to have largely solved it.

The temp sensor is located behind the plastic knee panel on the driver's side. When the auto temp control is set to a warm temp, heat blows out of the floor vents, and the plastic panel gets fairly warm in the area of the sensor. If you pull the plastic panel off, you'll notice that there is a tube (for lack of a better word) molded into the back of the panel, into which the sensor (which itself has a tubular housing) appears to mate. However, even though the sensor has a foam gasket at its base, it doesn't actually project far enough to go into the tube molded into the panel, let alone seal with its gasket. The presence of the gasket suggests to me that it's a universal part, and that sealing surrounding air from the sensor is important (it's got a little fan that pulls air through the front of the sensor).

My theory was that the heat in this area was prematurely tricking the sensor into thinking the cabin was warm, when it actually wasn't.

So, I grabbed a small piece of foam pipe insulation (the cheap gray stuff you get at the hardware store for putting on copper water lines), glued the split in the foam together with super glue, and cut it to length such that it could be slipped over the sensor all the way to the base, and sealing against the back of the tube in the plastic knee panel when in place.

Now, I'm able to set the temp to 74, the cabin heats up, and the vents then blow moderately warm air to keep it consistent. I still have a bit of a chilly breeze on my face, but that appears to be from the defrost vent air blowing across the frigid hard top, and the resulting cold air falling down. Hard top headliners should fix that, I'd assume.
 

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I was considering swapping my automatic temp controller to a manual because of this issue. It works fine on short trips but eventually blows cold air. I hate constantly turning it upon longer drives. Did you test the fan direction? I assume it pulls air toward the front of the vehicle?

I'm going to give this a try. Thanks for the tip.
 

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Discussion Starter #5
Mine no longer seems to be blowing cold air, even when it was -5° outside. It starts out hot, fan speed high, then cools down to simply warm (and slower fan speed) after the cabin heats up, but that's about it. I still get a cool breeze in the face, but feeling the air from the vents, it's warm now. The cold radiating off the top is exaggerated by the air blowing across it. I occasionally turn it up a bit to compensate for it, but not up to 80°+ as I did before. This is all in full auto mode, BTW.

For 5 minutes' work and a few dollars, definitely worth a shot.

The fan in the sensor appears to pull air from your knees towards the front of the Jeep, and there are vents along the base for that air to escape.
 

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Discussion Starter #7
Here you go. This iteration has probably 1/8" gap still between the face of the gray insulation and the panel, so I'll probably make a revised version that's just a tad longer so that it completely touches. Still, seems to work nicely.
 

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Awesome! Thanks for posting and the pics! This is something I will be doing shortly.
 

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If that was the case, all JK's with auto climate control would have this issue. Mine does not, it blows very hot whenever I ask for heat, no matter if it's cold or hot inside the cabin.


.
 

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If that was the case, all JK's with auto climate control would have this issue. Mine does not, it blows very hot whenever I ask for heat, no matter if it's cold or hot inside the cabin.


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Blowing cold air is not a big problem with mine until it gets cold, maybe 20 degrees F or less. It's worse the colder it is and is usually not noticeable until about 1 hr into a drive.
 

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No need to turn it up to 80 after adding the foam. Setting the temp dial to 72 now feels like it did when it was set to 80 prior to adding the foam.


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