AC Compressor on and off issue
6/17/18, 04:36 PM
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AC Compressor on and off issue
Hey what’s up everyone, I have a 2013 Mustang 3.7 my ac compressor turns on and off every 5 to 6 seconds. It will not cycle constant . Does any have any idea what this could be? They ac has been charged it is full no leaks.
6/17/18, 07:15 PM
#2
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The conditions for a cycling are either high pressure issue or evaporator coil (inside the dash) is icing over. It could also be low pressure/refrigerant.
Insufficient refrigerant/lower pressure: There's a specific switch in there for that. If there's not enough base (off) pressure the compressor will not run. Old cars it would, but old cars had oil that didn't run off elsewhere and stayed in the compressor enough so it could just run. These cars today have oil in the refrigerant that'll run off and hide elsewhere and so if there's not enough refrigerant to oil up the compressor, the compressor won't run until there's enough base (off) pressure, which should mean there's oil in the system, so it's safe to run.
Evaporator coil too cold/icing over: The reason there's a sensor in there is to prevent the icing. Icing means airflow stops. No airflow=no cool, and also makes the icing worse. So if the temperature probe in there is seeing it's too cold, it'll turn off the compressor. Things warm up, the ice goes away, it'll kick back on. Over and over if it's happening. A bad sensor could be the problem here if it's not icing.
How does it ice? Well, a lower amount, but enough to be over base pressure, of refrigerant could do it. System can run with a lesser amount and work, but it'll actually make the temp of the evaporator too cold and ice up. Other factors, but that's most likely if it's happening and it's not the sensor.
Lastly, too much refrigerant and/or a high pressure issue. Too much refrigerant will cause the pressures overall to be too high, and so when the system sees that, it'll turn off the compressor to save it from being hammered and destroying it. The other would be there's a blockage of some sort causing a high pressure indication.
So overall, I'd say double check both high and low pressure readings to ensure they're correct. If they are, you either have a sensor issue, or there's some computer issue or wiring, and at that point you might be talking a shop if you don't have the equipment/knowledge.
Hope that helps. I'm sure I'm wrong about something or forgot something, and someone will come in and slap me around for it and correct things, but I think I got it...
Good luck to ya! Oh, yeah, and Welcome to the Forums!
Insufficient refrigerant/lower pressure: There's a specific switch in there for that. If there's not enough base (off) pressure the compressor will not run. Old cars it would, but old cars had oil that didn't run off elsewhere and stayed in the compressor enough so it could just run. These cars today have oil in the refrigerant that'll run off and hide elsewhere and so if there's not enough refrigerant to oil up the compressor, the compressor won't run until there's enough base (off) pressure, which should mean there's oil in the system, so it's safe to run.
Evaporator coil too cold/icing over: The reason there's a sensor in there is to prevent the icing. Icing means airflow stops. No airflow=no cool, and also makes the icing worse. So if the temperature probe in there is seeing it's too cold, it'll turn off the compressor. Things warm up, the ice goes away, it'll kick back on. Over and over if it's happening. A bad sensor could be the problem here if it's not icing.
How does it ice? Well, a lower amount, but enough to be over base pressure, of refrigerant could do it. System can run with a lesser amount and work, but it'll actually make the temp of the evaporator too cold and ice up. Other factors, but that's most likely if it's happening and it's not the sensor.
Lastly, too much refrigerant and/or a high pressure issue. Too much refrigerant will cause the pressures overall to be too high, and so when the system sees that, it'll turn off the compressor to save it from being hammered and destroying it. The other would be there's a blockage of some sort causing a high pressure indication.
So overall, I'd say double check both high and low pressure readings to ensure they're correct. If they are, you either have a sensor issue, or there's some computer issue or wiring, and at that point you might be talking a shop if you don't have the equipment/knowledge.
Hope that helps. I'm sure I'm wrong about something or forgot something, and someone will come in and slap me around for it and correct things, but I think I got it...
Good luck to ya! Oh, yeah, and Welcome to the Forums!
Last edited by houtex; 6/17/18 at 07:16 PM.
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