How to Test Refrigerator Capacitor with Multimeter (Whirlpool & GE Guide)

If your Whirlpool or GE refrigerator is making a humming noise but refusing to start, learning how to test refrigerator capacitor components is the most important diagnostic step you can take. While many people blame the relay, the real culprit is often the “battery” that gives the compressor its kick.

This small cylindrical part acts like a turbo boost for your compressor. If it fails, the compressor stalls, overheats, and your food spoils. In this guide, we will troubleshoot whirlpool fridge capacitor symptoms and perform the definitive ge refrigerator start relay test.

We will also show you how to safely discharge the stored electricity inside the capacitor (a crucial safety step) and use a multimeter to verify if the part is dead.

Understanding the Part Before You Learn How to Test Refrigerator Capacitor

To understand why this part is so important, you have to understand the physics of an electric motor. Your refrigerator’s compressor is a heavy-duty motor. Just like a car engine needs a starter motor, a compressor needs a massive surge of torque to start spinning.

The Capacitor stores a concentrated electrical charge. When the thermostat calls for cooling, it releases this energy in a split-second burst. This extra jolt is fed into the motor windings to start the piston moving against pressure.

Start Capacitor vs. Run Capacitor

Before you use our guide on how to test refrigerator capacitor units, identify which type you have:

• Start Capacitor (Black): Stays in the circuit only for a split second. High rating (100+ MFD).
• Run Capacitor (White/Silver): Stays in the circuit 100% of the time. Lower rating (10-20 MFD).

Common Whirlpool Fridge Capacitor Symptoms

Capacitors rarely fail “quietly.” They usually give off distinct signs before they die completely. If you notice these issues, do not wait for the fridge to stop cooling entirely.

1. The “Hard Start” (Dimming Lights)

Does your kitchen light flicker or dim noticeably every time the fridge turns on? This indicates the compressor is drawing massive amperage because the capacitor isn’t helping it start.

2. The “Click-Hum-Click” Cycle

This is the classic sound of a start failure. The motor hums trying to spin, fails, and then the Overload Protector clicks to cut the power.

SAFETY WARNING: Discharge Before You Test Refrigerator Capacitor

STOP. Read this section twice.

A capacitor is designed to store electricity. Touching the two metal terminals with your bare fingers can result in a painful shock, even if the fridge is unplugged.

How to Discharge Safely

1. Unplug the Refrigerator.
2. Get an Insulated Tool: Use a screwdriver with a plastic or rubber handle.
3. Short the Terminals: Touch the metal shaft of the screwdriver across both metal terminals of the capacitor simultaneously.
4. Listen: You might hear a “pop.” This is the stored energy releasing.

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Tools You Will Need

To perform this test accurately, you cannot guess. You need specific diagnostic tools.

• Digital Multimeter: Ideally one with a “Capacitance” mode (MFD or µF).
• Needle-Nose Pliers: To pull the wire connectors off.
• Nut Driver: To remove the back panel.

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Step 1: Locate the Part to Test Refrigerator Capacitor

For most Whirlpool and GE models, the capacitor is located next to the compressor at the bottom rear of the fridge.

1. Pull the fridge away from the wall and remove the lower back panel.
2. Locate the Start Relay (the plastic box plugged into the side of the black compressor).
3. Whirlpool Style: Look for a white part clipped directly onto the relay.
4. GE Style: Look for a white cylinder mounted separately on the cabinet floor.
5. Remove It: Use pliers to disconnect the wire terminals. Do not pull by the wire itself!

Step 2: Visual Inspection

Before you learn how to test refrigerator capacitor internals, look at the outside.

• Bulging: Is the top domed or swollen?
• Leaking: Is there oily residue?
• Burnt: Are terminals melted?

If you see any of these, the capacitor is bad. Replace it immediately.

Step 3: Guide on How to Test Refrigerator Capacitor with Multimeter

If the capacitor looks physically perfect, you must test its internal chemistry. The most accurate way is using the “Capacitance” mode (Symbol: -||-).

1. Check the Label: Look for the rating, such as “12-15 MFD”.
2. Set Your Meter: Turn the dial to the Capacitor symbol/MFD setting.
3. Connect Probes: Place one probe on the left terminal and one on the right terminal.
4. Read the Screen:
   • Good Reading: The number should be within 10% of the rating on the label.
   • Bad Reading: If the number is significantly lower or zero, the capacitor is weak.
   • Dead Reading: If the meter says “OL” (Open Loop), it is disconnected internally.

Step 4: The “Resistance Trick” (Alternative Method)

If your meter lacks a capacitor mode, you can still learn how to test refrigerator capacitor functionality using the standard Ohms (Ω) setting.

1. Set Your Meter: Turn the dial to a high Ohms setting (20kΩ).
2. Touch the Terminals: Place probes on the capacitor.
3. Watch the Screen:
   • Good: The numbers should climb rapidly until hitting “OL”. This means it is taking a charge.
   • Bad: If it stays at “OL” instantly or stays near “0”, it is dead.

Brand Specifics: Whirlpool vs. GE

While the testing physics are the same, the failure patterns differ by brand.

Whirlpool Fridge Capacitor Symptoms

Whirlpool fridges often use a “Run Capacitor” attached to the start relay. When these fail, the fridge might still run, but the compressor will run very hot. If you replace the relay on a Whirlpool, always replace the capacitor too.

GE Refrigerator Start Relay Test

GE models commonly use a standalone capacitor. On GE units, the Start Relay often fails before the capacitor. If your capacitor tests “Good,” you must perform a ge refrigerator start relay test (shake test) to confirm the relay isn’t the real problem.

Conclusion on How to Test Refrigerator Capacitor

Knowing how to test refrigerator capacitor with multimeter probes is a 5-minute diagnostic job that separates the pros from the guessers. It allows you to definitively prove if a part is bad before you spend money.

If your multimeter shows the part is dead (OL or Low MFD), a $15 replacement is usually all it takes to get that compressor humming again.

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If the capacitor tests fine but the fridge still clicks, your Start Relay might be the issue. Check out our guide on how to test and replace the start relay for the next logical step.