A condenser, or capacitor, can be tested using a condenser tester. The tester applies a high voltage to test for leakage and measures the storage capacity, or capacitance, of the part. The condenser can also be checked using an analog multimeter.
When testing the condenser with a multimeter, first isolate the condenser from the engine by disconnecting the lead wire. The small metal connector at the condenser's end is the power link, and the metal case of the part is the grounding point. Discharge the part by shorting the lead wire.
Next, switch the meter to ohms and place the red-colored lead into the meter's resistance connector. Insert the black lead into the meter's common connector. Set the resistance range to the highest setting. Link the test leads before zeroing the meter.
Touch the red lead to the condenser's power connector, and apply the black lead to the condenser's metal case. The needle on the meter should move slightly toward the right before dropping back to the left. Hold each lead in place for approximately 20 seconds. If the test shows any other reading, then leaking is indicated, and the condenser must be replaced.
Remove the leads for this part of the test, and reverse the application or placement. Movement of the needle indicates the part is good, while any lack of movement indicates a replacement is needed.