I have a 2001 Excursion and a 1994 F-150 and both have the same problem. The air conditioner is on when I turn the vent to any position including the ones that are not AC. What gives here?
How do you know the A/C is on?
I think its normal for Fords to run the A/C in all modes except vent and off.
I have a 2000 Ford Explorer and see the same thing. It seems to be a function of the temperature setting though. If I have the temp set to the low end area of the dial, I get cold air in the various vent settings, otherwise not. I assumed it was by design, but I think that Ford should be a little more clear about how this works.
Even at the high end of the temperature dial, the AC still runs. It’s just that so much hot air is mixed in that it overpowers the AC. This is normal and is done for maximum comfort. (It drys the air out.) You are worried over 0.5 MPG difference at the most.
The Fords I am most familiar with can engage the AC compressor in everything but Vent, FLOOR and Off. The Def, AC. MAX, Mix (def/floor) will all have AC running if the temp is high enough to keep the low side pressure low enough.
DW’s ZX2 is a little different. It has another position in which the AC can be engaged, a panel/floor postion.
This is how my Civic is too. The AC is on to help dehumidify the air so they won’t fog up as bad(mostly for winter, but I just leave the button alone).