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Q: a/c question

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A/c button would flash 3x then go off... i figured out that means the system shut down the a/c. I added a can of refrig. and a/c work great... about 3 days later, same thing...3 flashes and nothing. Finally brought to my garage and they said leak. Added new o rings to the low and high valve caps... they charged the system. They ran for 40 minutes on the lot and the a/c was perfect. Brought home and next day, hot day, a/c didn't work...light lit up, but luke warm air conditioning... that night, started car and a/c worked tremendously. That symptom has carried on and off for 2 weeks now. My garaged checked the systme and all the numbers were fine. SO leak seems to be solved, BUT still inconsistnet a/c, cold or hot. ITs' funny cuz as i think this thru, when it works, the temps are not that hot out...on blazing hot days, doesn't work. Any ideas????

My car has 90000 miles.
My car has an automatic transmission.

A: This is usually the result of an electrical...

This is usually the result of an electrical switch in the A/C system. Electrical components are uniquely affected by temperature. Even if the system is full, it can act as you have described. The system may have been low at first, but even a slightly low system should work fairly well.

It doesn't sound as if the mechanic has had the car while it is failing. There is no way to diagnose a system if it is working, even if it fails under different circumstances. There are several switches in the A/C system that turn the A/C compressor on and off. When the ambient temperature is high, the pressures in the A/C system will also be higher than normal. A mechanic will need to experience this to accurately diagnose the problem.

A couple things can happen to an A/C system when it is hot out:

If the cycling switches are out of specification, they can turn the system off. If the cycling switch gets hot, it will develop an open in the circuit and the compressor won't run. This may only happen under higher or lower temperatures.

The A/C condenser could be plugged with debris or the fan may not be pulling enough air over the condenser. The condenser is the radiator looking thing in front of the coolant radiator.

The compressor clutch may be getting too hot and slipping. Either way, the only way to know is for a mechanic to catch it while it is failing. If you want to have this checked, a technician from YourMechanic can come to your home or office to diagnose your AC and determine what needs repair.

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