hey gentlemen, so 2005 f-250 auto with the 5.4l. if i have the temp selector on cool and the vent selector on the defrost or defrost and vent setting the a/c condensor engages but not on any other setting and works normaly when i actually turn the dial to A/C and it blows from the proper vents, anyone else experience this, know if this is normal or if there is a cure? thanks guys.

 

The a/c evaporator is used as a dehumidifier when you are using the defrost modes. That is why the a/c compressor engages. Dan.

 

Exactly, they figure that if you need defrost then there is too much
moisture in the cab....

It doesnt really help if you are really trying to de-frost (melt the ice
from your window) because it cools the air even more... BUT, I think
there is a temp limit where the compressor wont turn on (too cold)..

 

thanks for the replys guys, something still seems strange. i have tried all the settings and the a/c runs on all settings except the dash vents so i cant just have the air circulate without the a/c on and also seems to defeat the purpose of having an a/c setting. i was hoping to increase the mpg a little but then again the designers have the heated mirrors on all the time too. i still like my garden tractor more than the truck haha.

 

I think I know what your saying.....that you can't turn the AC off excpt in the vent position. I too would rather have a separate controll for the compressor. I'd install one, but don't know the wiring well enough. Anybody out there know???

 

bunklash .... thanks for saying much better and shorter than me. thats exactally what i mean. so i guess this is normal operation?

 

Yup, according to my 150's owner's manual it's by design. I just figure the rest are supposed to be the same, 'cause they are!
Still like to hear from somebody how to wire in a cut-out switch.