I hate automatic climate controls systems. I specifically avoid them because of past experience that was not rewarding.

That being said, my 09 Ram Sport has the digital read out automatic a/c. I got a great deal on a demo and got stuck with the a/c.

Today, OAT was 54F and my temp select was on 70F. I get in the truck and the dang A/C comes on! It seems to me that vent air with some heat would have been in order. I would like someone to tell me when and why the compressor comes on. The book says that the system is a set it and leave it system. I guess it is if you want the compressor coming on most of the time even if the heater might be a better choice.

I have both the vent select and the fan selector on auto. Any help very appreciated.

 

Just press the AC button to kick it off.


If the sensor in the upper console is warm from being in the sun it could send a AC signal to the control unit to kick that on. It will automatically go to heat when the vehicle fully warms up and the sensor picks up the true temp inside the vehicle.

Mine did that too until it got really cold outside. Then the AC never kicks on.

You can use it in manual if you don't like the AUTO fan and area selection. Just set your temp and manually set your other controls to make sure the compressor does not come on.


Just to mention I have been pleased with the Dodge Auto HVAC. My old Chevy one didn't work nice at all the fan would always be on full blast until the temp was reached. This one works smoothly and doesn't try to blow you away.

 

Thanks for the reply. I understand that I can turn the compressor off, but it did not seem that it would be much of a hands off unit if I had to do that. I let the compressor run for an hour and it NEVER shut off. I turned it off manually and then shut the truck down for about 30 minutes, started the truck with it still in the auto position and bam the compressor came on again. I don't understand why it is doing this. I should not have to turn the compressor off if it is a set and forget system.

This is the reason that I like the manual systems the best. I seems like on the auto units, I end up running the in manual most of the time.

 

The compressor runs when it is in defrost to remove moisture from the air.

 

So then the compressor should run even if it's in manual climate control mode??

 

Most cars turn on the compressor automatically when you choose defrost mode. The Dodge boys over-thought this one on the new Ram. It will not allow you to recirculate when in defrost mode because it causes fogging of the windows. That will not happen when the compressor is on number one and secondly, the windows will clear much more quickly if you can choose recirculation with the compressor because you are not having to dehumidify the fresh air, but only the air in the cab. I had to read this in the owner's manual because my system would not let me do defrost/recir at the same time. If the compressor did not come on automatically, the engineers would be right, but not if you are going to bring the compressor in. Oh well, turn on the defrost and let it do its thing because that is all that it will allow!

 

Does anyone know why everytime I select auto on either the fan speed or vent selection dial, the A/C compressor comes on? I mean, it is 45 degrees OAT and inside temp is set on 70. Is there some type of software issue here? Does the climate control system think that since it is less than X, we need A/C to dehumidify to avoid foggy windows? It seems to me, it should go into delay until there is enough heat to get the air warmed to 70. I can take it off auto, turn off A/C, and the second I turn either dial to auto, the dang compressor kicks in and A/C is displayed. I usually do a work around and just leave it in manual, but I would like to know why it behaves this way. Thanks for input.