The main fuse is located in the engine compartment, inside the under-hood fuse/relay box (often called the power distribution box). It is labeled MAIN and is a high-amperage fuse that protects the vehicle’s primary electrical circuit. The exact amperage is printed on the fuse and shown in the lid diagram, but it’s commonly around 100A for many Hondas of this era.
This article explains where to find the main fuse on a 2003 Accord, how to identify it using the fuse box cover diagram, and what steps to take if the fuse is blown. It also covers safety considerations and when to seek professional help.
Location and identification in the engine bay
In the 2003 Honda Accord, the under-hood fuse/relay box—also referred to as the power distribution box—is mounted in the engine compartment. The box is typically situated on the driver’s side of the engine bay near the fender or the battery. The lid of the box includes a diagram listing each fuse and its function, with the MAIN fuse clearly labeled.
To confirm you’re looking at the right component, remove the lid and compare the diagram with the actual fuses inside. The MAIN fuse will be a large-diameter fuse among the other fuses and relays.
Once you locate the MAIN fuse, you can inspect or replace it as needed. Always use a fuse with the identical amperage rating to avoid electrical damage or fire risk.
- Park and turn off the engine. Set the parking brake and open the hood to access the engine compartment.
- Locate the rectangular under-hood fuse/relay box (power distribution box) on the engine bay. It is a plastic housing with a removable cover.
- Remove the cover by pulling the tabs or releasing the clasps, and set the cover aside where it won’t be damaged.
- Consult the diagram printed on the inside of the cover to locate the fuse marked “MAIN” and note its amperage rating.
- Carefully pull the MAIN fuse out with a fuse puller or insulated pliers to inspect it.
- Visually check the fuse for a broken or melted element. A test with a multimeter can confirm continuity if you’re unsure.
- If the fuse is blown, replace it with a fuse of the same amperage rating. Do not substitute a higher rating.
- Reinstall the fuse and the box cover, then close the hood and test the vehicle’s electrical systems.
- If the new MAIN fuse blows again, there may be a short circuit or a malfunctioning component drawing excessive current; seek professional service to diagnose the issue.
In practice, locating the MAIN fuse is straightforward once you access the engine bay and read the lid diagram, but handling the main power circuit carries safety risks. If you’re unsure about performing inspection or replacement, contact a qualified mechanic.
Safety notes and additional guidance
Always disconnect the battery only after the engine is off and the keys are removed if you are performing in-depth electrical work. Use insulating tools and wear eye protection. Never bypass the main fuse or modify the fuse box wiring. If you suspect a persistent electrical fault, have the vehicle inspected to prevent a potential fire or damage to critical systems such as the engine control module or ABS.
Summary
For a 2003 Honda Accord, the main fuse sits in the engine bay’s under-hood fuse/relay box (power distribution box), labeled MAIN on the lid diagram. Replacement requires matching amperage, and if the fuse continues to blow, a deeper electrical fault may be present and warrants professional diagnosis. The fuse box diagram on the cover is your best quick reference for identifying the exact fuse and its rating.