This automotive maintenance tutorial was specifically written to assist owners of the 4th generation ND (2016, 2017, 2018, 2019, 2020 & 2021) Mazda MX-5 Miata in checking or changing a blown electrical fuse or a faulty relay.

Owners of other Mazda vehicles such as the Mazda2 (Demio), Mazda3 (Axela), Mazda5, Mazda6 (Atenza), CX-3, CX-5, CX-7, CX-9, RX-8 and MPV may also find these DIY instructions to be helpful.

The ND generation MX-5 Miata is equipped with the relatively newer style of "low profile" mini blade electrical fuses.

No tools are needed to access and replace any of the fuses in the engine bay fuse box or the interior passenger compartment electrical panel.

The first two steps are to open the hood and then move to the right (driver) side of the engine bay.

The black plastic somewhat square looking engine bay fuse box is located just to the right of the 12V automotive battery and behind the driver side headlight housing.

Pull the cover straight off the fuse box.

Turn over the cover to view the fuse location diagram. There is also another fuse location diagram in the owner's manual.

You'll also see the few spare fuses and the white plastic fuse puller tool.

Remove the tool from the back side of the cover. If the tool is missing, you could use a pair of needle nose pliers with rubber insulated handles.

Insert your finger into the notch on the access cover and gently pull it out of the kick panel.

There is also another diagram in the owner's manual.

Place the jaws of the tool over the fuse you'd like to check or change.

Pull the old fuse straight out of the socket.

To check the condition of the old fuse, hold it up to a light bulb.

If the thin metal bar or strip in the translucent plastic center of the old fuse appears to be burnt or broken, the old fuse is most likely "blown" and it should be replaced.

If the thin metal band in the middle of the old fuse appears to be intact, it is most likely still good.

Since new fuses are so inexpensive, it should still be replaced as part of your electrical issue troubleshooting process.

Re-attach the fuse puller tool to the holder on the underside of the engine bay fuse box cover.

If you suspect that a faulty relay is the cause of your problem, the easiest way to troubleshoot the issue is to simply replace the automotive relay. You could also use a digital multimeter tool to test the old relay. Pull the old relay straight out of the socket and push in a new one of the amperage rating.

Lower the fuse box cover back into place.

Push on the cover to secure the retaining clip.

Line up the access cover for the interior electrical panel.

Gently push the cover back into place to secure the retaining clips.

Test the electrical component you were having issues with such as the horn, radio, wiper blades, headlights, tail lights, power driver's seat, interior lights, power windows, 12V power outlet, etc.

If you are still having the same problem, there may be a shorted out wire or the component itself needs to be replaced.

For more, check out all of my 2016-2021 Mazda MX-5 Miata DIY Repair & Maintenance Guides.