2005 Mazda 3, A/c compressor and condensor replaced less than two years ago. Last summer I noticed the A/C keeps cycling on and off repeatedly. I have had the unit charged, emptied, charged again, checked, and no one can tell me why it still turns on and off by itself. I am worried this compressor will lock too and I'll have wasted all the money I spent. I've already spent a few hundred bucks trying to find the problem but no one can figure it out. An ideas? It's nothing I can fix myself, I'm not a very handy lady when it comes to anything besides oil, tire pressure, or gassing up my ride. Thanks in advance!

  • Until you get someone to check the high side and low side pressures of your air conditioning system while it's operating, nothing can be said. – Al_ May 19 '19 at 15:00

That's normally the sign of low refrigerant charge. But since you've had that done, I suspect you've got a bad evaporator temp sensor or a failing expansion valve.

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  • It's not a sign of low refrigerant charge in that case. Being it a TXV system the pressure switch/transducer is located on the high side pressure only so it will never cycle on suction pressure like on American cars equipped with "cycling clutch orifice tube" systems. If the pressure were too low, it just wouldn't turn on. On the other hand, this can make the compressor run with a refrigerant charge that is so low that it can reduce compressor lubrication and damage it. It's either overpressure (stuck closed TXV, a clog somewhere, condenser/radiator fan not turning on) or electrical fault. – Al_ May 19 '19 at 14:58

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