A/C Compressor cycling

[Codered]

Any info on what to check when your A/C compresser cycles when the heat is on, not defroster, just heat blowing on your feet and midlevel vents. Thanks

 

[rb142]

The AC is on in any setting except just the vents. That is normal [though stupid]. If you put it on mid-level vent only and the AC is still on, then something is wrong.

 

[Codered]

What do you mean by vent only.

 

[masospaghetti]

If you select vent only or floor only, the a/c compressor should not cycle on. Any other setting will run the compressor. I also don't know why Ford did it this way, unless they were encouraging the a/c to be used more often (and maybe prevent the seals from drying out).

 

[Codered]

I have the fan set as low as possible, temp on hot and the mmode switch if you will set to the split setting floor and vents like above the radio and in the corners and am I right in saying the a/c compressor should not cycle at all

 

[1998Exp]

I believe that all automotive climate control systems work like that. The air goes through the evaporator first, because cooling it down removes moisture. Then it's reheated as needed. Sounds silly, but I still remember driving cars that had no A/C. In the winter it was a constant battle to wipe the fogging off the windows.

If you select vent only or floor only, the a/c compressor should not cycle on. Any other setting will run the compressor. I also don't know why Ford did it this way, unless they were encouraging the a/c to be used more often (and maybe prevent the seals from drying out).

 

[intelisevil]

I have the fan set as low as possible, temp on hot and the mmode switch if you will set to the split setting floor and vents like above the radio and in the corners and am I right in saying the a/c compressor should not cycle at all

From my 1999 Mercury Mountaineer Owner's Manual: "The air conditioning compressor will operate in all modes except FLOOR and VENT. However, the air conditioning will only function if the outside temperature is about 10°C (50°F) or above."

The setting that sends air to both the floor and dash vents WILL cause the A/C Compressor to operate!

It sounds as though you're system is working as designed by Ford.

 

[koda2000]

I have the fan set as low as possible, temp on hot and the mmode switch if you will set to the split setting floor and vents like above the radio and in the corners and am I right in saying the a/c compressor should not cycle at all

I suggest you try reading your owner's manual. The A/C will run on any setting except VENT and FLOOR. This is done to remove humidity from the cabin. If you don't like it you can unplug the A/C clutch for the winter.

 

[Codered]

I appreciate everyones input but it seems there is some contradiction, The compressor is cycling on when I have heat blowing on the split setting of floor and the vents above the radio not defroster vents. One of you is saying a/c is on for every setting but vent and floor. If that is the case then there is a issue.I am apppreciative of your help, just trying to figure it out

 

[rb142]

No there isn't an issue. That is the way it is designed. Having it set to heat has nothing at all to do with whether the AC compressor runs. If you have the mode switch set to dash vent and floor position, the AC compressor will run by design. You may not want it to work that way, but that is the way it is built. If you put the mode switch on dash vent ONLY or if you put the switch on floor vent ONLY, the AC will be off. Any other setting and the AC will run.

As indicated, the AC is enabled when the top (defroster) vent is enabled to remove moisture from the air and help defog the windows. However, that does not explain the vent/floor combined mode engaging the AC, which is the mode that always bothered me.

 

[koda2000]

No there isn't an issue. That is the way it is designed. Having it set to heat has nothing at all to do with whether the AC compressor runs. If you have the mode switch set to dash vent and floor position, the AC compressor will run by design. You may not want it to work that way, but that is the way it is built. If you put the mode switch on dash vent ONLY or if you put the switch on floor vent ONLY, the AC will be off. Any other setting and the AC will run.

As indicated, the AC is enabled when the top (defroster) vent is enabled to remove moisture from the air and help defog the windows. However, that does not explain the vent/floor combined mode engaging the AC, which is the mode that always bothered me.

You are 100% correct. Turning up the TEMP has nothing to do with whether or not the A/C runs in VENT/FLOOR mode. All turning up the TEMP does in that mode is open the door to the heater core. When the heater core door is closed you get 100% A/C. That's the part he doesn't get.

 

[masospaghetti]

I appreciate everyones input but it seems there is some contradiction, The compressor is cycling on when I have heat blowing on the split setting of floor and the vents above the radio not defroster vents. One of you is saying a/c is on for every setting but vent and floor. If that is the case then there is a issue.I am apppreciative of your help, just trying to figure it out

The compressor will run on all settings except VENT ONLY and FLOOR ONLY. VENT + FLOOR split setting will run the compressor.

 

[mark2016]

The compressor will run on all settings except VENT ONLY and FLOOR ONLY. VENT + FLOOR split setting will run the compressor.

Yep works on mine like that. Click on, click off, repeat over and over. Only really noticeable when stopped.

 

[sirdigalot]

mine does that too, it is annoying but also much easier for cabin "climate" control, leave the general workings the same all models then just vary the blend door by servo depending on set temp (if you have the digital CC) that is my next project when i eventually get my car computer working right.... add temp settings to it this method makes it much easier than having to control the A/C compressor separately

 

[intelisevil]

The compressor will run on all settings except VENT ONLY and FLOOR ONLY. VENT + FLOOR split setting will run the compressor.

Yes, what he said!

 

[Codered]

Hey guys, Thanks for the input, Koda, Rb, Maso were right on with their info, mine was operating properly, didnt seem right but it was floor only or vent only gets no compressor, the mix setting for floor and vent gets the compressor. Thanks again, alot of input and knowledge here

 

[SoNic67]

I also don't know why Ford did it this way,

De-humidification.
Any modern car with Automatic AC will do that, because (live) people exhale water vapors (besides CO2) that will accumulate in the cabin and fog up the windows.

The AC will not work also if outside temperature is low enough.

 

[masospaghetti]

De-humidification.
Any modern car with Automatic AC will do that, because (live) people exhale water vapors (besides CO2) that will accumulate in the cabin and fog up the windows.

The AC will not work also if outside temperature is low enough.

I understand that, but sometimes I don't want the A/C to run (if its not humid, for example, and I don't need cooling). Waste of fuel. Also, there's no way to use RECIRC unless I want max a/c. Would be much better to have separate A/C and RECIRC buttons like virtually all new cars and most older Japanese cars.

 

[SoNic67]

Yeah, probably a cabin humidity sensor would be required too to calculate the dew point of the windshield. Complicated and not really saving that much.
The AC will stop working if is cold enough outside also - the only case when you would use re-circulation, you won't use that recirc when is 80-100F outside.
And the AC energy savings are minimal for larger engines (4-5 liter), unlike the smaller 4 bangers that have manual AC.
Even on those smaller engines, when you hit the windshield defogger the AC starts - regardless if the AC button is pressed or not.

 

[intelisevil]

I understand that, but sometimes I don't want the A/C to run (if its not humid, for example, and I don't need cooling). Waste of fuel. Also, there's no way to use RECIRC unless I want max a/c. Would be much better to have separate A/C and RECIRC buttons like virtually all new cars and most older Japanese cars.

It looks like you need to track down a good wiring diagram and install a switch.