Review
How to Test & Replace the Compressor Start Relay in a Refrigerator
AAZparts Team
Updated on June 25, 2025
5 min read
The compressor start relay is a small but essential component of a refrigerator. It helps start the compressor, which is responsible for cooling. When this relay fails, the compressor may not turn on, leading to temperature issues, spoiled food, and increased energy consumption.
The compressor start relay is a small yet vital component in any refrigerator. Its job is to help start the compressor, which powers the cooling system. When this relay fails, the compressor may not run, leading to a range of refrigerator compressor problems—such as rising temperatures, spoiled food, and higher energy bills.
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What Is a Compressor Start Relay?
The compressor start relay is an electrical switch that briefly sends high-voltage current to the compressor when the fridge cycles on. Once the compressor is running, the relay disengages.
If the relay is faulty:
- The compressor won’t start.
- The fridge can’t cool properly.
- You may notice several signs indicating the refrigerator compressor might be failing .
Signs Your Refrigerator Compressor May Be Failing
The compressor is the heart of your refrigerator’s cooling system—when it starts to fail, your appliance can quickly lose its ability to preserve food. Recognizing the early warning signs of a faulty compressor can help you act before the problem worsens. Here are the most common symptoms:
- Unusual Noises: A buzzing, rattling, or clicking sound coming from the back of the fridge is often the first sign of compressor trouble. Most modern refrigerators operate quietly, so any persistent noise is worth investigating.
- Inconsistent or Inadequate Cooling: If your fridge suddenly stops keeping food cold, or the temperature fluctuates unexpectedly, it could point to compressor failure. While other issues like a faulty refrigerator thermostat or door seal can also affect cooling, a failing compressor is one of the most serious culprits.
- Overheating or Warm Air Around the Fridge: Excessive heat behind or beneath the unit—especially near the compressor—could indicate it's overworking or on the verge of failure.
- Compressor Fan Issues: If the internal fan stops spinning or works intermittently, it can lead to poor coolant circulation. This reduces cooling efficiency and may eventually cause the compressor to overheat or shut down.
- Chemical or Burning Odor: A refrigerant leak may give off a sharp, chemical-like scent. In some cases, it can smell like burning rubber or plastic—both signs that demand immediate attention.
- Dirty Condenser Coils: When condenser coils are covered in dust and grime, the compressor must work harder to expel heat. Over time, this strain can cause the compressor to fail. Cleaning the coils every six months can extend your appliance's life.
- Electrical Failures: Water damage or power surges can affect the refrigerator’s control board, which regulates the compressor. Faulty signals from the board may prevent the compressor from turning on or functioning properly.
- Frequent Cycling On and Off: If your fridge turns on and off rapidly or runs in short bursts, it may be due to a malfunctioning start relay or an overheating compressor that’s shutting down prematurely.
If you notice any of these signs, it’s best not to wait. Contact a certified refrigerator technician to inspect and service your appliance. In many cases, compressor issues can be resolved quickly and cost-effectively—especially when caught early.
How to Test the Compressor Start Relay
Tools You’ll Need:
- Multimeter (with continuity test or resistance mode)
- Flathead screwdriver (to access the relay)
- Gloves (recommended for safety)
Step-by-Step Instructions:
Step 1. Remove the Relay
- Carefully disconnect any wires connected to the start relay.
- Pull the relay straight off the compressor terminal. (Take a photo beforehand for reference.)
Step 2. Check for Obvious Damage
- Shake the relay gently. If it rattles , it’s likely burned out .
- Inspect it for signs of charring, discoloration, or a burnt smell .
Step 3. Test Continuity or Resistance
Using a multimeter :
Option A: Continuity Test
- Set the multimeter to the continuity setting .
- Touch the probes to the two terminals on the relay.
- If you hear a beep , the relay has continuity (it’s good).
- No beep = broken relay.
Option B: Resistance Test
- Set the multimeter to ohms (Ω) .
- Touch the probes to the relay terminals.
- A typical resistance range is 3–12 ohms . If you get no reading (OL) or 0, it’s faulty.
Tip: Some start relays also have an overload protector inside. If it’s blown, the multimeter will show no continuity.
How to Replace a Faulty Start Relay
The compressor start relay is a small but critical component that helps the compressor kickstart when the fridge cycles on. If your fridge isn’t cooling properly or is making clicking sounds, a faulty relay could be the cause. Replacing it is a manageable DIY task for many homeowners.
Tools & Materials You’ll Need:
- Flathead screwdriver
- Needle-nose pliers (optional)
- Multimeter (to test the relay, optional)
- Replacement start relay (check compatibility with your fridge model)
- Safety gloves (recommended)
Step-by-Step Instructions:
Step 1. Locate the Compressor and Relay
- Remove the rear access panel at the bottom back of the fridge using a screwdriver.
- The compressor is a black, cylindrical component with wires connected to it.
- The start relay is usually a small plastic box attached to the side of the compressor.
Step 2. Remove the Old Start Relay
- Carefully disconnect any wires attached to the relay. (Take a picture beforehand so you can reconnect them properly.)
- Gently pull the relay straight off the compressor terminal. Some models may also have a cover or clip that needs to be removed first.
Step 3. Check for Damage or Burning Smell
- If the relay rattles when shaken , is discolored, or has a burnt odor, it’s definitely faulty.
Step 4. Install the New Start Relay
- Line up the new relay’s prongs with the compressor terminal and firmly push it in .
- Reconnect the wires to the proper terminals (refer to the photo you took).
Step 5. Reassemble and Test
- Reattach the back panel and plug in the refrigerator .
- Listen to hear if the compressor kicks on. Let the fridge run for a few hours and check if it begins cooling properly.
Final Thoughts
If your Frigidaire, Whirlpool, or Kenmore refrigerator isn’t cooling, don’t panic. A bad compressor start relay is a common issue and often the root cause of refrigerator compressor problems . Look out for clicking sounds , warm fridge despite working lights , an overheating compressor , or frequent circuit trips . Testing and replacing the relay is straightforward—and could save your fridge from costly repairs.
The good news? Testing and replacing a bad relay is a relatively quick and inexpensive DIY fix —and far more affordable than replacing the entire compressor.
At AZParts, we offer a wide selection of high-quality, OEM-compatible refrigerator parts, including compressor start relays , capacitors , temperature sensors , evaporator fans , and more. Whether you're repairing a broken relay or troubleshooting other cooling issues , AZParts has everything you need to keep your refrigerator running at its best.
Explore our full refrigerator parts collection today—and save your fridge (and your wallet) from major repair bills tomorrow.
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