I just swapped out the coolant on my '06 F150. In order to stir things up I turned on the heater for the first time.
The panel still showed A/C when in the auto mode and set for 90 degrees. Why would the air conditioner pump be on in the heat mode?
Is this normal, or do I have a problem?
Thanks,
LKG907

 

That's normal.

 

Did you have it in straight "heater only" ?or was it in the "defrost & heater" position?

The A/C Compressor is activated automatically when either MAX A/C, Defrost and Floor/Defrost are selected (if manual heat / AC system) .... (and in AUTO, Defrost and Floor/Defrost if you have ATC [automatic temp control] ) ... because besides cooling, the A/C system dries the air of humidity, makes defrost work much faster.
This is why these newer defrosters work so much faster than those of older cars and trucks. My '77 didn't do this originally, I added a toggle switch to flip the compressor on when I needed defrosting and it really speeded things up with it.

See .... Climate Controls section in the owners manual.