tribonse

Hi all.Just bought a brand new 2017 V6 Mustang.

Noticed the air conditionercompressor keeps cycling on and off about every 10 seconds with the air conditioner on(coolest temperature setting,recirculation button on,fan at low setting).Can even see the compressorclutch go on and off when I looked at it with the hood open.Air blowing through the vents seems cold at all times.But noticed that when I turn the fan speed to the highest setting the compressor stays on and does not cycle on/off. Is this cycling normal? Is this some kind of energy/fuel saving feature? Don't remember this happening on other cars I have owned in the past(including my previous 2014 Mustang).Thanks for any info.

tribonse

Can anyone on here check if they have the same problem?

08'MustangDude

IT has to cycle, it cannot run continuously or the EVAPORATOR will freeze.

dsmit412

It could be low on Freon that will also cause the compressor to cycle more often. There is a low pressure switch built into the system.

08'MustangDude

IF it's low, as the other reply, THEN it's leaking... Get your A/C system repaired.
If you just bought it, then it's under warranty.

With the fan on HIGH, you're moving the cold air off the evaporator with warm air from
outside. It will continue to run because it has not reached the temperature threshold.
This is also combined with the ECU, knowing it's on high, so it can keep the clutch
engaged. When at IDLE, like I said, HAS TO CYCLE so the system does not freeze.
MINE does it, and every car I pull up next to at a light, IDLE, you can HEAR their clutches on
the A/C compressors cycling.

If you want the "low on Freon" answer, then take it back and have it looked at, plain and
simple.

dsmit412

Not true statement all dependent on the outside temperature how much it will cycle. It does not have to cycle at idle to prevent freezing.

tribonse

Thanks for responses.Some more info if it helps.It cycles about every 10 seconds at idle and at highway speed.I always have it on recirculation.Will try it with recirculation off next time I drive to see what happens.Seems to do it in all outdoor temperatures it seems.And as I said it seems to be blowing cold at all times.And at idle you can physically and visually see/feel the compressor cycling.

I have checked other peoples cars at work(all 2017 and 2018 new 4 cyclinder Fords but not Mustangs) but obviously not the same engines as my 6 cylinder. And none of them do this.Their compressors stay on.My work truck is also a 2017 Ford Transit and it does not do it.

I have an appointment on June 14 at my dealership to check it.I hope it is normal.And I hope they don't make it worse some how.

08'MustangDude

With RECIRC on, you drastically reduce the humidity inside the car. That air
also gets colder and colder, thus the compressor does NOT need to be on all
the time, at a full duty cycle. The evaporator does not stay cold for long, so
it cycles the compressor on and off to keep the evaporator cold. If it continually
ran in RECIRC, the system would freeze.

If using outside air, it can stay on if it's hot enough outside. You said it only
does this when your fan is on the LOW wetting. I am basing my answers
off your detail. When on MAX, it changes the parameters for compressor
engagement. You also said you lose no cooling effect as it does it. If
it were to get warm, and cold as it cycles, then there is a problem with the
refrigerant pressure/level.

I have an '08 Mustang, when I come to a atop at a light, or I am idling
the car, I can hear the A/C clutch cycle. I checked the pressure in
the system, and it is fine. If I put the HVAC fan on MAX, as you do, it
stays engaged a lot longer.

The only other thing would be a relay or other electrical failure. If it's a bad
relay, it's loosing contact, then latching again...

The A/C cycling switch is another area, but, again, you're not loosing the
cold effect. It is on the low pressure side of the A/C line. It is a pressure
issue or switch failure if it's not blowing cold, or as cold as it used to. When
it detects low pressure, it disengages the clutch. If the switch is not operating
correctly, then the AC system will not be pressurized correctly. Still, as you
say, you lose no cold effect.

You're not having a RAPID effect, right? When it runs for 10 seconds, how long
is the clutch disengaged before it comes back on?

Over pressure will also cycle the clutch.

You should be getting, optimally, 44 degree air from the vents.

JimC

Enough of the crap guys. and '08MustangDude your posts do come off as angry, condescending and argumentative.

08'MustangDude

Whatever.