3 yr old refrig has started making a humming sound for approx 10 seconds and stops with a click
HI. First you will need verify where the buzzing is located. If it is near the compressor area, it could be the start up relay. If the buzzing is coming from the actual control board area(in the middle section, on the backside behind a access panel, or the lower left section of the compressor area), this will be the control board(PCB).
I suspect a faulty starter relay. Use the procedures below to confirm failure.
I would recommend to check the relay first, then the compressor last to confirm total failure. If both devices test out ok, this will lead to a failed main power control board.
The compressor relay starts the compressor. A fault relay can result in the compressor failing to cycle on. The relay is accessed from the lower rear of the refrigerator. The compressor relay can be accessed by removing the terminal cover box. The cover is held on by tension or with a retaining clip. On some units. the relay may not be covered at all.(each model may vary). Beneath the terminal cover(if equipped), you will find the compressor relay, and the overload protector as well. The electrical terminals of the compressor motor are located here also. Remove the compressor relay by pulling it straight off from the compressor, gently. Pull the wire off of the side terminal of the relay. It is connected with a slip on connector. Firmly pull the connector, do not pull on the wire. You may need to use a pair of needle-nose pliers. Inspect the connector and terminal for corrosion. If either is corroded they should be cleaned or replaced. There are two types of relays you may encounter, wire coil and solid state. If the relay has an exposed wound wire coil it can be tested for continuity. Otherwise, the relay is of solid state design and requires specialized equipment for testing. Test the relay with a ohm(multimeter), for continuity. Set the meter to the ohms setting X1. With the relay upside down, place the probes into the terminals labeled "S" and "M"(the labeling may vary on each modle). The meter should display a reading of zero ohms, indicating continuity (or if using a continuity tester, it should light up). With the probes still in place, turn the relay over. You should hear the click of the magnetic switch engaging. The meter should now display an ohm reading of infinity (or the tester should not light up). Turn the relay upside down again, place the probe on the "S" terminal and place it on the side terminal labeled "L". The meter should now display a reading of zero ohms (continuity). Turn the relay over and the reading should change to infinity. With the relay upside down place one probe on the "L" terminal and the other probe on terminal labeled "M". The meter should display a reading of zero ohms. Turn the relay over and the reading will stay the same, zero ohms. Now, if the relay fails these described tests, it should be replaced asap.
COMPRESSOR TEST PROCEDURE
The compressor is accessed from the lower rear of the refrigerator. Generally the same proximity of the relay. The compressor motor can be accessed by removing the terminal cover box. The cover is held on by tension or with a retaining clip. The main testing points will be the actual terminal post that hold the relay, gently pull the relay of the terminal box on the side of the compressor, and use the relay holding probes for testing. Once the relay is removed, Place one probe on any terminal and then touch the other probe to each of the other two terminals. The multimeter should display a reading of zero ohms. Be sure to set your meter to 1X before beginning. Now move the first probe to a different terminal and test the other two terminals with the other probe. Finally, move the first probe to the last terminal and test each of the other terminals with the other probe. Every test should have continuity with the multimeter displaying zero ohms. If the compressor motor does not pass all of these tests, the compressor will require professional service. Now test the compressor for ground. With the multimeter still set to X1, touch one probe to bare metal on the compressor housing (it may be necessary to scratch away a little paint to expose the metal). Touch the other probe to each of the three terminals in turn. None of the terminals should have continuity; the multimeter should display a reading of infinity. If any of the grounding tests show continuity, the compressor will require professional service.
Dec 20, 2009 |