Step-by-Step Capacitor Testing and ReplacementThe run capacitor is the single most frequently replaced component in condenser fan motor repair. It is inexpensive, easy to replace, and responsible for the majority of “motor won’t start” service calls.Step 1 — Shut Down and Lock Out PowerTurn off the thermostat, then open the electrical disconnect box near the condenser unit and pull the fuse block or flip the breaker. Apply a lockout/tagout device. Wait at least 5 minutes to allow residual charge to dissipate, then verify with a non-contact tester that power is off.Step 2 — Discharge the CapacitorUsing a properly rated discharge tool, touch the probes to the HERM, FAN, and COMMON terminals of the capacitor (on a dual-run capacitor). Hold contact for a few seconds on each pair. Confirm discharge with a DMM set to DC volts — reading should be near zero.Step 3 — Photograph the WiringBefore disconnecting any wires, take a clear photo of the terminal connections. Capacitors are typically color-coded, but a reference photo eliminates guesswork during reinstallation.Step 4 — Test the CapacitorWith the capacitor removed and discharged:Set your DMM to the capacitance (µF) measurement mode.Connect the probes to the appropriate terminals.Compare the measured value to the rating printed on the capacitor label. A tolerance of ±6% is typical; anything beyond ±10% warrants replacement.Also check for shorts: set the DMM to resistance mode — a good capacitor will show a brief low reading that climbs to infinity as it charges through the meter.Step 5 — Select a ReplacementMatch the following specifications exactly:Microfarad (µF) rating — Must match within ±5%.Voltage rating — Match or exceed. A 370V cap can be replaced with a 440V cap; never go lower.Physical size and terminal type — Ensure the replacement fits the bracket and wiring.Step 6 — Install and TestConnect wires per your reference photo, secure the capacitor in its bracket, restore power, and verify operation. With a clamp meter, check the running amperage against the FLA on the motor nameplate.