NA Miata Main Fuse / Fusible Link Replacement DIY

The main fuse is one of the few parts that can leave you stranded without warning on an old Miata. The symptoms of a failed main fuse are similar to that of a dead battery. If you know that your battery is okay, but nothing happens when you turn the key in the ignition, the main fuse is one of the most likely culprits.

Fortunately they are very cheap and easy to replace. It’s highly recommended that you buy a spare one to keep in the glove box in the event of an emergency.

Parts Required:

• Main fuse

Tools Required:

• 10 mm socket / ratchet with extension
• flat head screw driver

Instructions:

1. Locate the fuse box under the hood next to the windshield washer bottle. Remove the cover by pressing in the tab and lifting up.

2. Note the black 80A main fuse. Undo the 2 10 mm nuts securing the fuse box to the bracket.

3. Lift the fuse box up and pry open the cover on the right side using the flat head screw driver. You will see a 10 mm bolt which needs to be removed.

4. Tilt the fuse box the other direction and you will see a second 10 mm bolt that needs to be removed. You will need an extension on this side.

5. With both bolts removed, the main fuse should pull right out. You can then install your new main fuse. Note the wide “prong” openings on both sides for the 2 bolts you just removed.
6. Snap the right-hand cover back down in to place. Place the fuse box back on the mounting studs and tighten down the 2 10 mm nuts removed in step 2. Clip the fuse box cover back on top.