From Dryers to Blenders: An Appliance Blog

How To Test A Refrigerator Start Relay

If your refrigerator makes clicking noises, the inside doesn't seem cool enough, or won't start at all, you may have a bad start relay. 

A start relay comes on after getting a signal from the thermostat when the interior reaches the set temperature. The relay should make a click upon starting. Before you replace it, follow these tips to test the start relay.

Prepare to Work

For this project, you need: 

  • work gloves
  • set of screwdrivers
  • needles-nose pliers
  • multitester

Move the refrigerator from the wall slightly, and unplug the cord. If it has an ice maker, disconnect the water supply line with an adjustable wrench.

Lay the water supply in a container to catch water. Turn off the ice maker water supply by rotating the valve to the right, or flip the metal lever to "OFF".

Remove the Start Relay

The start relay is on the bottom rear of the refrigerator. There are two types of relays: wire-wound and solid state. Wire-hound relays have visible copper wires twisted around a plunger. A solid state relay is plastic without winding. 

Use a screwdriver to detach the access panel screws. Remove wire-wound relays with pliers. Solid state relays should pull off the terminal.

The relay is the small box with wires attached to the compressor, a cone-shaped device. Follow the compressor wires to the metal terminal box, and detach the box by depressing the clips or springs with your finger to reveal the relay. 

Note how wires attach. Disconnect the female wire connector from the male wire connector. Use your fingers to detach the relay switch.

Inspect the Relay

Sniff for burn smells on the relay, which indicate possible damage. If there are no burn smells, inspect the relay for rust on the copper winding. Remove rust with a wire brush, and test the relay again. 

To further test a solid state relay, shake it. If it makes a rattling noise, it is likely defective.

Test a Wire-wound Relay with a Multimeter

Wire-wound relays can be checked with a multi-meter. A solid state relay should only be tested by a professional.

A wire-wound relay commonly has two terminal marked "S" and one terminal marked "M".To test a wire-wound relay, insert one probe to one "S" terminal and the "M" terminal. The digital display should read zero or the needles should move to 0.

Flip the relay over with the probes still attached. You should get an infinity, or "1", reading. Flip the unit over. 

Remove a probe from the "S" terminal, and insert it into the "L" terminal, You should get a 0 reading. Flip it over, and look for an infinity reading. Repeat the test with probes attached to "S" and "M" terminals. You should get a 0 reading for each test. 

Hook everything back up, and restore power. If you don't trust your skill to test or replace the relay, contact a home appliance repair service.