Proper Connection of Fridge Thermostat Wires: A Comprehensive Guide

When dealing with a refrigerator's thermostat, it can be a challenging task to connect the wires correctly, especially when the wires are of different colors and no clear documentation is available. In this guide, we will walk you through the correct connections for your fridge thermostat.

Introduction to Refrigerator Thermostat Wiring

Thermostats in refrigerators are designed to control the temperature by connecting and disconnecting wires to the compressor and heater. Typically, a refrigerator thermostat requires just two wires, but manufacturers use various color codes to denote connections. This can create confusion, especially when trying to connect the correct wires to the start relay.

Understanding the Wires and Connections

Your fridge thermostat has four wires: blue, yellow, green, brownish, and red. Here’s a breakdown of each wire's role and how to determine the correct connections using an ohmmeter or voltmeter:

Blue - This wire typically controls the heater for defrosting the freezer. Yellow and Green - These wires are often used for different modes or settings on the thermostat. Brownish - This wire is usually connected to the compressor start relay. Red - This wire is usually connected to the compressor start relay as well.

Steps to Connect the Fridge Thermostat Wires

Follow these steps to properly connect the wires to the start relay:

Determine the roles of each wire: Use an ohmmeter or voltmeter to test the wires and identify which ones are connected when the thermostat is turned down or on specific settings. Look for a click or a change in voltage when the contacts are engaged. Identify the power wire: One of the wires will be "hot" with power when the contacts are engaged. This wire will power the compressor's start relay and connect to the compressor when the desired temperature is reached. Identify the defrost wire: The blue wire (or any other colored wire connected to the defrost setting) will control the heater for defrosting the freezer. Connect the wires to the start relay: Once you have identified the correct wires, connect them to the start relay. Ensure that the compressor will only receive power through the start relay and will stay in run mode until the desired temperature is reached. Test the connections: Before fully connecting the wires to the compressor, use a test light with a socket and two wires to check the components. Run the current through the bulb to ensure it heats up before connecting it to full power. A 100-watt incandescent light bulb will suffice for this test.

Additional Tips and Recommendations

Here are some additional tips to ensure a successful connection:

Use heat shrink tubing: If you need to splice any wires, use heat shrink tubing to insulate the connections and prevent corrosion from moisture. Use a breaker: Ensure you have a working breaker in case the wiring is different from standard wiring. Check the compressor: Use a Kill-A-Watt meter to test the compressor and the starter relay. The compressor should draw a lot of wattage at start-up and then drop to about half that wattage as it runs. A malfunctioning relay can damage the compressor. Check for overheating: If the compressor or wires get hot very quickly, it indicates that the start relay is stuck or the starter windings are fried. In this case, a new compressor or repair by an electrician may be necessary.

By following these steps and tips, you can successfully connect the fridge thermostat wires and ensure that your refrigerator operates efficiently. If you encounter any issues, it might be best to seek assistance from a professional electrician.

Keywords: fridge thermostat, wire connection, compressor start relay