how to bypass contactor on ac unit


How to Bypass Contactor on AC Unit


Air conditioning units are an essential aspect of our daily lives, offering respite from sweltering summers. However, just like any other electrical equipment, they can encounter issues over time. One common issue faced by AC unit owners is a faulty contactor. The contactor is responsible for controlling the flow of electricity to the condenser unit, ensuring efficient cooling. If the contactor fails, it can hinder the proper functioning of the AC unit. In this article, we will explore five effective methods to bypass the contactor on an AC unit and restore its functionality.

The Importance of the Contactor

The contactor plays a crucial role in the operation of an AC unit. It acts as a switch, allowing or interrupting the flow of electrical current to the condenser unit. When the thermostat in your home signals the need for cooling, the contactor engages, allowing electricity to reach the condenser and compressor. This initiates the cooling process. Conversely, when the desired temperature is reached, the thermostat signals the contactor to disengage, cutting off the electrical supply.

Method 1: Identifying the Contactors

Before attempting to bypass the contactor, it is vital to understand its location and appearance within the AC unit. The contactor is usually located near the condenser unit and can be identified as a small rectangular box containing multiple wires. Familiarize yourself with its appearance to ensure precision and careful handling during the bypassing process.

To begin, turn off the power supply to the AC unit from the main electrical panel. This step is crucial to prevent any accidents or electrical shocks while working on the unit. Locate the contactor box and carefully open it to access the wire connections. Take note of the various wires attached to the contactor, as this knowledge will be crucial in the bypassing process.

Method 2: Bypassing the Contactor with Jumpers

One of the simplest and most effective methods to bypass the faulty contactor is by using jumpers. Jumpers are small pieces of wire that can temporarily connect two points, allowing electricity to flow continuously. This method is only recommended for advanced DIY enthusiasts or individuals with electrical experience. If you are unsure about your capabilities, consult a professional technician to avoid any mishaps.

To bypass the contactor using jumpers, begin by disconnecting the wires from the defective contactor. Identify the wires connected to the power supply and the ones leading to the condenser unit. Connect the power supply wires directly to the wires leading to the condenser using jumpers. Take utmost care to ensure secure connections and proper insulation of the jumpers. Once the bypassing process is complete, restore the power supply and test the AC unit for functionality.

Method 3: Utilizing a Contactor Bypass Switch

For those who require a more convenient and permanent solution, utilizing a contactor bypass switch is an excellent option. A contactor bypass switch is designed to provide a simple and safe alternative to a faulty contactor. The bypass switch serves as a bridge, enabling the uninterrupted flow of electricity to the condenser unit.

To install a contactor bypass switch, ensure the power supply to the AC unit is disconnected. Locate the wires leading to the condenser unit and the power supply wires connected to the contactor. Install the bypass switch between these two sets of wires, ensuring secure connections. Once the bypass switch is installed, restore the power supply, and test the AC unit for functionality.

Method 4: Using a Contactor Relay

A contactor relay is another effective device to bypass a faulty contactor. This method requires a basic understanding of electrical components and wiring. Before proceeding, ensure you are comfortable working with electrical connections or consult a professional technician.

To bypass the contactor using a contactor relay, turn off the power supply to the AC unit. Remove the wires connected to the faulty contactor and connect them to the contactor relay. Refer to the manufacturer's instructions for proper wiring. Once the connections are secure, restore the power supply and test the AC unit to ensure it operates as intended.

Method 5: Seeking Professional Assistance

Bypassing a contactor on an AC unit is not a simple task and can be potentially hazardous if not performed correctly. Therefore, it is highly recommended to seek professional assistance when dealing with electrical components and wiring. Professional technicians possess the necessary expertise and equipment to troubleshoot and resolve AC unit issues safely.


Bypassing a faulty contactor on an AC unit can help restore its functionality in cases of breakdown. In this article, we explored five different methods to bypass a contactor, ranging from using jumpers to installing contactor bypass switches and relays. Remember to exercise caution when working with electrical components, and if unsure about your capabilities, it is always advisable to consult a professional technician. By following these methods, you can ensure your AC unit remains in optimal working condition, providing cool relief during scorching summers.


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