Safety: Unplug the unit. Capacitors can hold charge; discharge safely or have a technician handle testing.

Steps:

Visual inspection: Remove the rear panel and inspect the compressor wiring harness and capacitor for burn marks, bulging, or leaking.
Check capacitor: If you have a capacitance meter, disconnect the capacitor and measure its value. Replace it if it is more than ±10% off the rated µF or shows physical damage.
Inspect harness: Ensure all connectors to the compressor, overload, and relay are tight and not heat-damaged.
Compressor test: With power off, measure resistance between compressor terminals (C-R, C-S, R-S). Values should be finite and not shorted to ground. A short to ground or extremely low resistance indicates a failed compressor.
Board check: If compressor and capacitor test good, the control board’s current-sensing or relay output may be faulty and require replacement.
Professional help: Compressor replacement requires refrigerant handling and should be done by a licensed technician.

E7 error; fan may run but compressor does not start or stops quickly

Possible Causes