sport trac AC

[John Sheldon]

I'm new to this thrd and just got a 2004 Sport Trac. So far I like it. Question; the AC compressor seems to stay on regardless of the position of the rotary switch. Is this normal? if not where do I look to fix it? I rather chilly when the outside temp is in the 50's and I suspect I will get better fuel milage if the compressor wasn't running.
Thanks
Rotary John

 

[ncranchero]

When MAX A/C, A/C, PANEL/FLOOR and DEFROST is selected the A/C compressor will operate if the outside temperature is above approximately 43°F.

When OFF, PANEL and FLOOR is selected the A/C compressor should not operate.



If the air conditioning is always on it could be a Circuit short, bad A/C cycling switch, bad A/C control relay or bad function selector switch.

 

[Gus Gorilla]

What he said. (ncranchero).
Also, isn't the compressor clutch ground side switching? So a short to ground would cause constant running. Shorts to ground are usually easy to track and correct.

 

[John Sheldon]

Thanks guys. I didn't realize the AC would come on in the vent positions. Works as you said.

 

[-junior]

I think I'm seeing the same thing as well. Had the PANEL/FLOOR vents on and the temp set to cold the other day and the air was freezing (with an outside temp of 75).

@John, did you hear anything when OFF was selected on the dial? In my setup when I select OFF I'm hearing a slow hiss, like decompression, almost like a beach ball with a pinhole slowly deflating.

I've had the panel bezel off a couple times installing a double-din, would it be possible to create a short ncranchero and gus were talking about by removing that. If I can remember correctly, the fan gauge cluster stays in when the bezel is removed.

Did you ever find a solution for your problem?

 

[John Sheldon]

junior: yes. the AC operates as ncranchero says. The compressor runs in all but "off", "Floor" & "panel". It will cycle on your temp setting. The hissing you hear when switching to off I suspect is the vaccuum lines from the floo/panel/defrost selector gate letting go (its normal)

 

[ncranchero]

Sometimes the high side pressure bleeding off is also a pretty good hissssssssssss!

 

[-junior]

Thanks guys, I just tried this out, and you're 100% correct. I was leaving the knob in the floor+panel all the time, so my compressor must have been running constantly until the warmer weather came for me to notice.

Testing this out if you go panel only I get hot fresh air, but as soon as you go panel+floor get icy cold.

Thanks again for the info!!

 

[MoonMagic]

I don't get this thread? According to the manual, if you have the rotary switch in the panel/floor position, you should be getting outside air, not A/C air. I am definitely getting A/C in that position. Why is this? Thanks.