AC stays engaged all the time

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Ricks Ram

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The sensor has the metal clip on it that actually connects to another clip mounted in the windshield. Are you saying that the actual sensor is no longer connected to the wire or is it still there and just not mounted to the windshield? The windshields are different for the ATC and non ATC trucks whoever replaced your windshield should have switched the Rain Sensor and Humidity Sensor to the new windshield.

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Kgibson1315

Kgibson1315

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The sensor has the metal clip on it that actually connects to another clip mounted in the windshield. Are you saying that the actual sensor is no longer connected to the wire or is it still there and just not mounted to the windshield? The windshields are different for the ATC and non ATC trucks whoever replaced your windshield should have switched the Rain Sensor and Humidity Sensor to the new windshield.

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I guess the sensor got lost when the truck was wrecked. My windshield has no mounts for the sensor, but my truck is equipped with the sensor options. I have both wires, but no sensors. I'm assuming the humidity sensor is small and fits behind the little cover you posted a pic of?
 

TheEnder

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My 2016 Chrysler 300 does the exact same thing, the only time the compressor doesn’t run is when the climate controls are set to off. A/C button is useless, stays on with it pressed or when it’s not pressed. Also stays on when the recirculate button isn’t pressed.


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Ricks Ram

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I guess the sensor got lost when the truck was wrecked. My windshield has no mounts for the sensor, but my truck is equipped with the sensor options. I have both wires, but no sensors. I'm assuming the humidity sensor is small and fits behind the little cover you posted a pic of?
Yes, you should have an empty connector where the Humidity Sensor should be. Have you been able to find it? It appears they installed the wrong windshield and just said to hell with it. If you can verify the Humidity Sensor is missing I would feel pretty confident that is your issue. The compressor will stay on by default of it doesn't detect the Humidity Sensor.

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Kgibson1315

Kgibson1315

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Yes, you should have an empty connector where the Humidity Sensor should be. Have you been able to find it? It appears they installed the wrong windshield and just said to hell with it. If you can verify the Humidity Sensor is missing I would feel pretty confident that is your issue. The compressor will stay on by default of it doesn't detect the Humidity Sensor.

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Yes, I have two empty connectors. I believe one is for the rain sensing wipers and the other is the humidity sensor. I actually have the rain sensor in my glove box. I will have to order the humidity sensor. I see they are around $50. I wonder if it will work right since there is no where to mount it on the windshield?
 

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I wonder if it will work right since there is no where to mount it on the windshield?
I have mine tucked between the headliner and pressed up against windshield, seems to work good for me.
Even though it's called a humidity sensor, I'm pretty sure it's a dewpoint sensor due to the part that presses against the glass.OEM-Humidity-Sensor-Fits-for-Chrysler-Fiat-Jeep~2.jpg
The sensor measures both temperature and humidity to determine if the windshield will fog up.
 

Ricks Ram

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Yes, I have two empty connectors. I believe one is for the rain sensing wipers and the other is the humidity sensor. I actually have the rain sensor in my glove box. I will have to order the humidity sensor. I see they are around $50. I wonder if it will work right since there is no where to mount it on the windshield?
It should definitely make the compressor stop engaging every time you turn on the system. Since my truck doesn't have the mounting tab on the windshield either I just have mine slid between the windshield and the headliner. I actually think the pic MPgrimm2 posted with the sensor slid into the hedliner is my truck. In any case I'm not sure if the actual Humidity Sensor works as well that way but the compressor should stop running all the time. 99% of the guys that convert their trucks to ATC put them in the same place I did and the system seems to work ok.

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Kgibson1315

Kgibson1315

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It should definitely make the compressor stop engaging every time you turn on the system. Since my truck doesn't have the mounting tab on the windshield either I just have mine slid between the windshield and the headliner. I actually think the pic MPgrimm2 posted with the sensor slid into the hedliner is my truck. In any case I'm not sure if the actual Humidity Sensor works as well that way but the compressor should stop running all the time. 99% of the guys that convert their trucks to ATC put them in the same place I did and the system seems to work ok.

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Cool! I'm ordering the sensor today! I had no idea about the humidity sensor causing my problems. This is what makes this forum awesome! Thanks again for the replies and answers! I will post an update when I get the sensor.
 

Nystagmus

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My 2014 Longhorn has the same issue. A/C runs regardless of the switch setting.
I know this because of the whine when the A/C is engaged.
 

rvance

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Can't help. I live in Texas and I only turn off the AC about 2 days a year.
 

crash68

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I live in Texas and I only turn off the AC about 2 days a year.
I bet I probably turn mine off on the same two days here in Michigan... LOL!
 

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All modern vehicles have their A/C running constantly (or at least cycling on/off) This is to keep the coolant lines and seals properly maintained. It's been proven that running them this way makes them last a lot longer than heating up the engine bay and not running them.
 

grumpyb

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I haven't checked my 2019 2500 but most vehicles today are designed to turn the ac compressor on with defrost just to keep it lubricated , may have something to do with that,
 

Ricks Ram

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All modern vehicles have their A/C running constantly (or at least cycling on/off) This is to keep the coolant lines and seals properly maintained. It's been proven that running them this way makes them last a lot longer than heating up the engine bay and not running them.
We are not talking about the compressor cycling on and off. We are mostly talking about the compressor running constantly no matter what setting was selected including vent. We checked several trucks and the compressor did not engage on every setting like our trucks did after we upgraded to ATC. We figured out that we needed to add the Humidity Sensor in order for the ATC system to operate correctly.

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Tim Garceau

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Interesting you say that, I notice my fan only air blows much colder than the ambient temp once in a while during lower speeds.

Probably just get that sensor out of the loop or switch it off. I’ll dictate the A/C by the lighted button.

Thanks for tip!
 
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Kgibson1315

Kgibson1315

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Got the humidity sensor hooked up and drove the truck to work this morning. Turned on the vent and it works! I just used some double sided tape to stick the little sensor on the windshield and was able to stuff the cover into the headliner since I dont have the mounts on my windshield. Thanks again for the help everyone!
 

Ricks Ram

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Got the humidity sensor hooked up and drove the truck to work this morning. Turned on the vent and it works! I just used some double sided tape to stick the little sensor on the windshield and was able to stuff the cover into the headliner since I dont have the mounts on my windshield. Thanks again for the help everyone!
That's good to hear. I have no idea why someone would disconnect all the sensors from the widow and actually think they weren't nessisary. There really isn't much of a difference in price between the standard windshield and the Rain Sense/ATC style windshield so it makes no sense to install the incorrect windshield. At least you noticed the compressor was running on vent and added the Humidity Sensor to correct it.

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Kgibson1315

Kgibson1315

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That's good to hear. I have no idea why someone would disconnect all the sensors from the widow and actually think they weren't nessisary. There really isn't much of a difference in price between the standard windshield and the Rain Sense/ATC style windshield so it makes no sense to install the incorrect windshield. At least you noticed the compressor was running on vent and added the Humidity Sensor to correct it.

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I attached the rain sensor as well, havent tried it out to see if it works. I can live without the rain sensing wipers, but the A/C compressor running needed to be fixed. I can see how the humidity sensor got lost because that thing is tiny!
 

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