Hi All.
So I am a DIY guy for small work. Yesterday I was replacing coolant in my Lexus ES 300h 2013, I turned on the hot air to max so that all the coolant inside the heating unit (small radiator inside the dashboard) can also be drained, but I noticed that AC compressor was still on, and when I touched the AC pipes, they were super cold and both radiator fans were also on even when the car was not hot. Just to be clear, the temp to blow air was set to highest level, to my understanding AC compressor should be OFF here but it was not, hot air was blowing but AC was also working.

So the question is this normal? Do Lexus ES 300h 2013 AC compressor is reversible like home AC's that can make cold and hot air both? I thought in cars the hot air is only produced by air passing through the small heater radiator inside dashboard which holds the hot coolant.

 

Did you happen to have it on defrost? The AC compressor will turn on while on hot/defrost mode to remove moisture from the windshield.

 

The ac cycles on/off in auto when heating to control humidity levels in the cabin.

You can go into the menu and turn the ac off.