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Discussion Starter · #1 ·
All of the past year, I have had the ATC set to auto and A/C on. The water temperature stayed close to 200 degrees. The other morning it was dark and cool during my morning drive. I left the ATC on auto, but turned off the A/C. After about driving 10 miles, while at a traffic light, I noticed the water temperature was 222 and then shortly went to 225 degrees. I turned on the A/C, because I knew the high speed fan would come on. The temperature returned to normal.

I don't remember, but is the water temperature supposed to get that high when the A/C is off?
 

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Discussion Starter · #3 ·
I have a 1996 3.5L. When I have the ATC set to full auto, I'm pretty sure the A/C light on the push button is always on, unless I manually turn it off by pressing the button. The temperature ranges from like 197 to 209. It never gets up to 230.

When I watch the compressor/fan operation under the hood, I see the compressor run for a few minutes, then the high speed fan comes on while the compressor is still running. After the high speed fan has run for a couple of minutes, the compressor turns off. The high speed fan run a bit longer. The compressor turns off for about 30 seconds. Then it comes on and starts the cycle over.

It does this no matter what temperature the ATC is set to. I can turn it up to 85 and it does the same thing. The compressor comes on for several minutes, then off for 30 seconds, then on for several minutes and off for 30 seconds. Over and over as long as the A/C button is lit up on the ATC.

Maybe the pressure builds in the A/C system, which turns the high speed fan on? With the A/C on the water temperature never gets above 209.
 

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Oops! I guess I could have noticed that this is in the 1st gen forum. 😄 Sorry about that.

I don't have experience with first gen, so will leave this to someone else.
 

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I have a 1996 3.5L. When I have the ATC set to full auto, I'm pretty sure the A/C light on the push button is always on, unless I manually turn it off by pressing the button. The temperature ranges from like 197 to 209. It never gets up to 230.

When I watch the compressor/fan operation under the hood, I see the compressor run for a few minutes, then the high speed fan comes on while the compressor is still running. After the high speed fan has run for a couple of minutes, the compressor turns off. The high speed fan run a bit longer. The compressor turns off for about 30 seconds. Then it comes on and starts the cycle over.

It does this no matter what temperature the ATC is set to. I can turn it up to 85 and it does the same thing. The compressor comes on for several minutes, then off for 30 seconds, then on for several minutes and off for 30 seconds. Over and over as long as the A/C button is lit up on the ATC.

Maybe the pressure builds in the A/C system, which turns the high speed fan on? With the A/C on the water temperature never gets above 209.
This would be normal A/c fan operation to me. Fans are controlled via pressure transducer which determines line temp from pressure. Cycling is either done due to evap core temp dropping below set point, or pressure (heat) to high.
 

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Discussion Starter · #6 ·
While I was watching it cycle, I put my hand on the condenser and it was very hot when the compressor was running. The line to the evaporator was extremely cold.

During the winter, my 300's compressor rarely cycles on. I don't need cooling. Most of the time, the compressor is not running. During the summer the compressor runs more often, since I need more cooling. Seems logical to me.

With the Concorde, whether it's winter or summer, no matter what temperature the ATC is set to, the compressor runs the same amount of time over and over. I can set the ATC to 80 and the compressor runs the same amount of time. If I set the ATC to 70, the compressor runs the same amount of time. It only cycles off for about 30 seconds. Most of the time it's running. Why would the evaporator need to be ice cold in the winter and the ATC is set 80? It doesn't make sense to me.

Sometimes, I think the fans inside the car don't run that fast, because the evaporator is so cold.
 

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While I was watching it cycle, I put my hand on the condenser and it was very hot when the compressor was running. The line to the evaporator was extremely cold.

During the winter, my 300's compressor rarely cycles on. I don't need cooling. Most of the time, the compressor is not running. During the summer the compressor runs more often, since I need more cooling. Seems logical to me.

With the Concorde, whether it's winter or summer, no matter what temperature the ATC is set to, the compressor runs the same amount of time over and over. I can set the ATC to 80 and the compressor runs the same amount of time. If I set the ATC to 70, the compressor runs the same amount of time. It only cycles off for about 30 seconds. Most of the time it's running. Why would the evaporator need to be ice cold in the winter and the ATC is set 80? It doesn't make sense to me.

Sometimes, I think the fans inside the car don't run that fast, because the evaporator is so cold.
The condenser is what gets rid of the heat. So it's going to get hot. Odd note, A/c system do not cool air as much as they displace the heat from one area to another!

With winter, A/c also remove humidity, hence why without A/c takes extra long to clear windows. So with auto climate it will use the a/c system to remove humidity (not for cooling) to maintain a level that keeps windows clear. Specially if the humidity levels are high outside.

It is all normal operation.
 

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Most cars with electric fans do run cooler with A/C on compared to off, since it commands at least 1 fan, or fans on low.. sometimes based on condenser pressure and then fans on high if pressure is high enough. A lot of my cars run warmer with A/C turned off.. some cars turn the A/C compressor on based on climate control settings, especially in defrost mode..
 
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