Step 1
Power off your air-conditioning unit and unplug it.
Step 2
Remove the screws on the back panel of the unit where the fan is.
Step 3
Remove the back panel. The compressor will be just above the fan on the inside of the unit. Notice the electrical wires running to the compressor.
Step 4
Plug the air conditioner unit in, and turn your multimeter on. Set the knob on the front of the multimeter to "V." This means it will read in volts.
Step 5
Touch the end of the red lead running from the multimeter to the circuit where it connects to the terminal on the compressor. Touch the black lead to a nonelectrical metal object to ground the multimeter.
Step 6
Wait for the multimeter to produce a reading. If it doesn't, there is likely short in the wiring and a technician will need to repair the problem.