04 F250 a/c compressor kicking on and off

Bkpigs · Apr 5, 2019

My 04 F250 a/c compressor kicks off and on with the heat on or just turned to the blue but not selected for a/c. I didn't try it with the a/c selected. Didn't think of it until I was typing this. Do Ford's just do this to try and dry the air?

VicS · Apr 5, 2019

I think my 03 did, Can't remember if it
has a ac button or not. My 16 has a ac
button.

JayinNY · Apr 5, 2019

My brothers 99 and my 2000 both were doing that,
we had to recharge them with 134a or whatever it is
now..

MarkB_MI · Apr 5, 2019

In defog mode, most climate control systems kick on the A/C to reduce humidity. And many systems run the A/C in all modes, unless a problem (e.g. low charge) is detected.

4play · Apr 5, 2019

The a/c compressor will operate in the Defrost and Floor/Def (Mix) modes. This is to help clear fog from the inside of glass, the a/c system removes moisture from the air. This is the same op for most but not all vehicles.

Bkpigs · Apr 5, 2019

I have it set for the floor vents.

Steve@Advance · Apr 5, 2019

Cycling in heat/defrost mode, or when the inside air temp is low, or the airflow through the evaporator coil is low, is normal.

That's how the system prevents the evaporator coil from icing under low heat removal conditions.

It can also rapid cycle if the refrigerant level is low, but I don't think that is why your's is cycling. The last thing you want is to overcharge it, so try it in AC mode on a warm day with the fan on a higher setting, see if that doesn't settle down the cycling.

Bkpigs · Apr 5, 2019

I am just not sure why it is even kicking on with just the heat on and set for the floor.

showcrop · Apr 6, 2019

(quoted from post at 20:35:31 04/05/19) I am just not sure why it is even kicking on with just the heat on and set for the floor.

Bk I bet that you really have it set for defrost.

sixbales · Apr 6, 2019

Agree with JayinNY?..When the compressor is kicking on and off, its low on Freon.

Bkpigs · Apr 6, 2019

This is the last setting I tried.

MF#1 · Apr 6, 2019

The only positions that DON'T have the compressor running is Floor only and Dash vents only. The setting you have it on will run the compressor. Don't know why. The cycling means low Freon. AND when you run Max A/C you can't make it "warmer", that only works on regular A/C, Defrost, and the one your pic shows. Clear as mud, right;-)

docmirror · Apr 6, 2019

As heat is applied to air, the RH will increase, because hot air is less dense than cold air. As the RH goes up, condensation will tend to occur in some climates(not in the mtns of CO, but will in the swamps of LA). This condensation feels icky, and makes surfaces feel icky. To extract the higher RH from the warmed air, the AC is cycled, the water vapor is condensed onto the evaporator(Freon evaporation is happening INSIDE the coil), and is then deposited outside through the drain pan, and hose, right behind the right front wheel well.

I don't know if/why the floor setting does not run the AC, but above is why it runs in other positions. Happens on many modern cars.

Bkpigs · Apr 7, 2019

Thanks, I will try the floor only again. I appreciate the help!

04 F250 a/c compressor kicking on and off

Bkpigs

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JayinNY

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MarkB_MI

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4play

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Steve@Advance

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