What is the Main Relay (Computer/Fuel System) all about?
Relays play a significant role in controlling the various electronic components of your vehicle, and there are several that can be termed a “main” relay. However, when you speak of the vehicle’s main relay, you’re referring to the one that controls the computer and the fuel system. It’s the first thing to engage when you turn the ignition switch. Without an operable main relay, your car won’t run. On most makes and models, the main relay will be located in one of the underhood fuse boxes, but this varies from one manufacturer to another.
Keep in mind:
- The main relay is absolutely essential to vehicle operation.
- The relay is not inspected during routine maintenance and is designed to last for many years before needing replacement.
- Many other problems have similar symptoms, so professional diagnosis is important.
How it's done:
- The vehicle relay main panel is opened
- The defective main relay is removed
- The new main relay is installed
- The vehicle main relay panel is closed
- The vehicle is started and checked for operation
Without an operational main relay, your car will not operate. However, electrical problems can be complex, and the failure of the main relay could possibly be a symptom of an underlying problem. It’s important that our expert mechanics diagnose both the condition of the relay and any inherent causes that contributed to the relay’s premature failure.
What common symptoms indicate you may need to replace the Main Relay (Computer/Fuel System)?
- Fuel pump does not engage when ignition is turned to “on”
- Vehicle will not start
- Vehicle will not start when engine is hot
How important is this service?
There are few components as crucial to vehicle operation as your main relay. It operates both the car’s computer and the fuel system. If you experience any problems similar to the symptoms above, we recommend having your vehicle diagnosed immediately.