How to Measure Whether a Compressor is Good or Bad
2 Answers
Learn to identify the three terminals on the air conditioning compressor, which are S, R, and C. Among them, S is the starting winding, R is the running winding, and C is the common terminal. Then use a multimeter to measure the resistance. If the sum of the resistances between SC and RC equals the resistance between RS, the compressor is functioning normally.
When my car's air conditioning stops cooling, I first check the compressor myself. Start the engine, set the AC to the lowest temperature, and listen carefully for any humming sounds or lack of response from the compressor; if abnormal, it might be internally seized. Then check the pressure gauge to see if the high and low pressure values are within the normal range; too low indicates insufficient refrigerant, while too high suggests compressor failure. Use a multimeter to measure the coil resistance—normal values are a few ohms, and anything significantly higher or zero means it's faulty. The cleanliness of the AC system is crucial, and regularly replacing the filter can reduce the compressor's workload. Before working on it, it's best to have a professional shop evacuate the refrigerant to avoid leakage hazards. These small checks help me save a lot of repair trouble and extend the lifespan of the parts.
