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Upgraded 80A main relay for NA/NB

Upgraded 80A main relay for NA/NB

Regular price $109.00 USD
Regular price Sale price $109.00 USD
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The main relay powers your ECU and your ignition system, amongst other things. And when they fail, you're stuck. It's a mechanical relay, and after a couple of decades they just get tired.

Typical failure is immediate. The car will be working fine, then it simply won't start. This will strand the car wherever it sits - at a restaurant, at the beach, in your garage. We've even seen them fail mid-drive, which just shut the car down. Once the relays fail, they almost never come back.

Luckily, it's an easy fix. Swap out your relay as preventative maintenance or toss a new one in the glovebox. Yes, they're a bit expensive but they're cheaper than a tow. When you do remove the original, take a good look at the condition of the socket in the fusebox. If it's corroded, we recommend cleaning it to prevent a recurrance.

Mazda part JE16-18-811. Fits all NA and NB Miatas.


Instructions are not currently available.


Ships free in the US.

There are no shipping restrictions on this item.

What does it fit?


Emissions do not apply.


1 year



Customer Reviews

Based on 5 reviews
junkyard m.
Get one from the junkyard for free

Find a 91 - 01 Mazda MPV in your local junkyard and congratulations. Or get the normal relay from a junk Miata or junk Protege.

Note from FM: junkyard parts are a great way to save money, but be aware that they will not last as long as a new part. It may be worth keeping a spare in the car if your "new" relay is over 20-30 years old.

Exactly what I needed.

Fixed my issue immediately! Normal day drive turned into a tow after parking for a bit. Car is a 94 and has around 200k and is supercharged (extra heat).

Naturally I pulled the fuel pump first and generally took the car apart. No power was getting to the ECU or the fuel pump.

PRO TIP: Turn the ignition on, if you don't see the ECU and ABS light up on the dash then this will fix the issue.

SMP Relay

Unfortunately, Jason's advice on the SMP RY288 is incorrect. That relay is rated at 20 amps.

Save your money

I know this is a Denso relay; and thusly, the OEM replacement, but SMP makes the RY288, which a direct replacement for this, and is $25 cheaper on RockAuto.

Maneki N.
Replacement instructions

This is the main relay. 80 amps. Everything else depends on this. If you have no power in the fuse box, this is a good place to start. Location is in the fuse box. For removal instructions, try this URL. There three clips that hold the relay in place. Two on the short sides one on the 'engine' side. One of these can be released with a small screw driver. The others come lose by wiggling the component side to side. I know that's not very satisfying, but Mazda did not intend for this part to be replaced very often. A little 'dielectric grease' on the contacts is a good idea, going back in.