Jake5150

I've had my 2003 F150 for a few years now, and just now I started questioning something. When I have the temp set all the way to cool, and have it set to either panel and floor, or just floor, etc anything but AC and Max AC, is it still supposed to run the AC? I know for sure it is running it, but someone tried convincing me that it's supposed to just be outside air and not the AC but I'm starting to wonder if it's actually supposed to be like that or not. It's never been an issue which is why I never thought about it. Having it set like it is in the picture below, is it supposed to be blowing cold air from the AC?

77Ranger460

The compressor should only be running on AC and Max AC.

Jake5150

Strange, I wonder why it would be doing that then. I'm not really worried about it though, it's never seemed to cause any issues and I'll be buying a new truck in a few months anyways so I don't see any real reason to "fix" it.

link5631

The compressor actually runs pretty regularly on these trucks, even when AC is not selected. They turn off and on in order to keep the compressor circulating oil.

Your truck is working correctly and I wouldn't be concerned. You're not gonna get a huge drop in gas mileage, Ford designed the compressor to do this in order to keep seals lubricated and the system circulating. Most new cars actually do this as well.

mbb

Have you read. Your owners manual?
It explains operation.

Your ac ONLY vents thru panel when on

The other vent settings, are for outside air via fan

Exactly what the switch implies.

Really a half-baked design.

link5631

My owners manual states exactly what I had said. Unless I misunderstood or there's a different design?

white89gt

The compressor also runs when "def", and "flr&def" are selected.

al_c

I believe it comes on with the defog as well, right?

mbb

paker

As others said, AC runs at all positions except PANEL.