Refrigerator Compressor Start Relay: Symptoms & Replacement

What the LFX29945ST does

The compressor start relay provides a temporary boost of power to the compressor motor, helping it overcome initial inertia and begin its cooling cycle. It then disengages once the compressor is running.

Symptoms when this part fails

• Refrigerator not cooling
• Compressor clicks on and off rapidly
• Humming sound from the compressor area
• Refrigerator makes no noise, but light works

Compatibility

Fits the LG family. Specifically:

• Any unit originally equipped with OEM part number(s): LFX31925ST.
• Check the model/rating plate inside your appliance and compare it against the fitment table on the product listing before ordering — this guide does not list specific compatible models because Amazon does not provide verified fitment data through this pipeline.

Also replaces: LFX31925ST

Tools you'll need

• Screwdriver set
• Nut driver set
• Needle-nose pliers
• Multimeter (optional)

Difficulty: Moderate · Time: 30-60 minutes

How to install the LFX29945ST, step by step

1. Unplug the refrigerator from the wall outlet.
2. Move the refrigerator away from the wall to access the rear.
3. Locate and remove the compressor access panel.
4. Carefully disconnect the wires from the old relay.
5. Remove the old start relay from the compressor terminals.
6. Attach the new start relay to the compressor terminals.
7. Reconnect the wires to the new relay.
8. Replace the access panel and plug in the refrigerator.

Related troubleshooting

If swapping this part doesn't fix the issue, check these next:

• Refrigerator ice maker not making ice? 7 fixes for Whirlpool, Samsung, LG, GE and more
• How to clean refrigerator condenser coils: Whirlpool, LG, Samsung, Haier and more
• How to change a refrigerator water filter: Whirlpool, Samsung, LG, GE, Frigidaire