- 1). Turn off both of the air-conditioning system's circuit breakers. The inside unit's circuit breaker mounts in the inside panel box and the condenser's circuit breaker usually mounts in the service panel next to the electric meter.
- 2). Slip a screwdriver into the condenser fan's louver cover, the grill protecting the fan blades. Spin the fan blades with the screwdriver's blade. Replace the fan motor if the fan blade does not spin at all or it spins smoothly for a short period of time and stops abruptly.
- 3). Remove the condensing unit's electrical service panel, using the correct size screwdriver to loosen the mounting screws. The wires from the building enter the bottom of the service panel.
- 4). Locate the fan motor's capacitor, located in the condensing unit's service panel. A fan's capacitor provides a constant electric charge to the fan motor's windings as the voltage fluctuates. Some condensing units use a fan motor with two brown-colored capacitor wires while others use a fan motor with a single brown-colored wire. A fan motor with two capacitor wires uses a single-run capacitor, which has two wire terminals. A fan motor with a single capacitor wire uses a dual-run capacitor and the fan's capacitor wire attaches to the capacitor terminal with the "Fan" label. A dual-run capacitor has three wire terminals: a terminal for the common, the fan and the compressor.
- 5). Inspect the fan capacitor's housing. Replace the capacitor if it has a bulging or swollen lid, has an oily or slimy film on its housing or contains corroded wire terminals.
- 6). Pull the fan motor's brown-colored capacitor wires from the capacitor wire terminals, using needle-nose pliers for leverage. If the condenser uses a dual-run capacitor, pull the wire on the "Fan" terminal and the wire on the "C" or "Comm" terminal.
- 7). Turn a multimeter to its capacitance setting. Touch the multimeter probes to the capacitor's fan terminals. Compare the multimeter readout to the capacitor's stated capacitance rating, found on the capacitor's identification label. If the multimeter reading shows a drop of more than 10 percent from the stated capacitance rating, replace the capacitor. Replace the fan wires on the capacitor.
- 8). Turn on both of the air-conditioning system's circuit breakers. Turn the thermostat to its coldest setting. If the unit does not turn on, wait 5 minutes for the time-delay relay to activate.
- 9). Turn the multimeter to its voltage setting. Touch the multimeter probes against the contactor wire terminals, the relay located inside the condenser's service panel, and take a voltage reading. If the multimeter reads 0 volts, troubleshoot the contactor and the high-voltage power supply.
- 10
Turn the multimeter to its amperage setting. Clamp the multimeter amp probe over the fan's common wire, the black-colored fan wire. Compare the readout to the fan's stated amperage, using the fan's identification chart as a guide. If the multimeter reads 0 amps, replace the fan motor. If the multimeter readout exceeds the fan's stated amperage rating, replace the fan.
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