Quick Links

MegaSquirt Relay Board - Unassembled Kit
MegaSquirt Relay Board - Unassembled Kit
MegaSquirt Relay Board - Unassembled Kit
MegaSquirt Relay Board - Unassembled Kit
MegaSquirt Relay Board - Unassembled Kit

MegaSquirt Relay Board – Unassembled Kit

3.6666666666667 out of 5 based on 3 customer ratings
(3 customer reviews )
MegaSquirt Relay Board - Unassembled Kit


In stock


MegaSquirt Relay Board – UnAssembled Kit Part # MSRelay-K

Includes everything you will need to build your MegaSquirt Relay Board, complete with black anodized case.

Though the Relay/Power Board is not required, it is a convenience and reduces the chance of miswiring during the installation. The relay board provides a central place for all of the required relays, fuse protection, and external wiring for the MegaSquirt ECU. If you are installing MegaSquirt in a previously fuel injected engine you may be able to reuse all of your existing relays. If you are fuel injecting a previously carbureted engine you will need to install relays for the main ECU power, Fuel Pump, and FIdle circuit. You can do this manually or you can use the Relay Board to simplify this process.

Comes with DB-37 connector to be used to build your relay cable, and a “half-case” setup that serves as an enclosure and mounting bracket. The top of the relay board is exposed when the board is complete, but all the components are safe to install in an engine compartment.

Uses standard ‘mini-ATO’ style fuses. (not included) Recommended fuse values are:

  • 20 Amp main fuse
  • 10 Amp fuel pump fuse
  • 5 Amps fuses for INJ1 and INJ2 with a 4 cylinder engine, 7.5 Amps with an 8 cylinder.

You may need to change these values based on your needs. These are good starting values.

Make sure to check out our Relay Cable for connecting the Relay Board to your MegaSquirt ECU, and our Wire Bundle which comes in handy for wiring up all of the sensors/injectors/etc to the Relay Board.

For a tech/how-to video for installing your MegaSquirt Relay Cable into your car, check out our Tech & How-To Videos Page HERE.

Customer reviews

Rated 3.6666666666667 out of 5 stars
3 reviews
4 stars 0 0 %
2 stars 0 0 %
1 star 0 0 %

3 reviews for MegaSquirt Relay Board – Unassembled Kit

    Only logged in customers who have purchased this product may write a review.

    What are the four holes next to the fast idle relay?

    • These bring out the connections from DB37 pins 3 through 6 and allow you to connect wire leads to these. Our latest relay cable includes these connections populated.

    How do I connect wires to the three large power connections?

    • You may solder wires to these connections, or use a ring terminal and through bolt.

    Is there a cover available for the relay board?

    • The relay board is designed to use a half case without a cover.

    What wiring do I use with the relay board?

    • Use our Relay Cable to connect the Relay Board to the MegaSquirt, and the Wire Bundle to connect the relay board to the engine.

    How do I use the relay board with an MS3X?

    • The outputs that go to the main board are routed through the relay cable, while connections to the MS3X use a separate connector that bypasses the relay board.

    Questions & Answers

    1. 0 votes

      We generally don't recommend this with a MicroSquirt as there is not a harness for this application and, for motorcycle and powersports applications, the relay board is rather bulky.