Best Main Relay Conversion Kits: Top Picks for Smooth Starts

Looking for the best main relay conversion kits? We’ve tested and reviewed the top 10 options to help you fix starting problems fast and keep your car running smoothly.

Main relay issues can leave your car stranded. Fix starting problems fast with the right conversion kit. These kits replace faulty relays and keep your car running smoothly.

Honda and Acura owners often face main relay troubles. Upgrade your vehicle with a reliable conversion kit. Enjoy peace of mind and improved performance on the road.

We’ve tested and reviewed the best main relay conversion kits for you. Find the perfect fit for your car and drive with confidence. Let’s get started!

List of Top 10 Main Relay Conversion Kits

Title	Best For	Price
Farpida Main Relay Conversion Kit with Kill Switch fit for Honda Civic 1992-2001,CRV 1997-2001, Integra 1994-2001, Accord 1990-2002, Prelude 1992-2001	This kit is for Honda and Acura owners. It stops car theft and fixes start issues fast.	View on Amazon (paid link)
Main Relay Conversion Kit Compatible with 92-01 Civic, 94-01 Integra, 97-01 CRV, 93-97 Delsol, 90-02 Accord, 97-99 A cura Cl, 95-98 A cura Tl, 92-01 Prelude	This Main Relay Conversion Kit is perfect for car owners who want a reliable and easy upgrade. It’s great for those with older Honda or Acura models looking to improve performance and add security with a simple plug-and-play installation.	View on Amazon (paid link)
ZUDKSUY RZ-0063 Main Relay Conversion Kit, Replacement for Honda Civic/CRX 1988-1991, Replacement for Acura Integra 1986-1993, Replaces 39400-SH3-003	This is best for Honda car folks who need a quick fix. It will keep your ride top notch.	View on Amazon (paid link)
39400-SH3-003 RZ-0063 Main Relay Conversion kit Compatible with 88-91 Civic/CRX, 86-93 Integra, 86-90 Legend, 92-94 Vigor, 86-89 Accord, 85-91 Prelude,XYgdhqpt	This Main Relay Conversion Kit is perfect for Honda/Acura owners who need a simple, plug-and-play solution to replace their old main relay. It’s ideal for DIY enthusiasts looking for a direct fit with no modifications required.	View on Amazon (paid link)
Vkinman Main Relay Conversion Kit with Kill Switch, Replacement for Honda Civic CR-V Accord Prelude 1990-2002, Acura Integra CL TL 1994-2001	This Vkinman Main Relay Conversion Kit is perfect for Honda and Acura owners who want a simple, reliable upgrade. It’s easy to install and adds extra security with a built-in kill switch.	View on Amazon (paid link)
XYgdhqpt Main Relay Conversion Kit for Compatible with 92-01 Civic,94-01 Integra,97-01Crv,90-02 Accord,Main Relay Harness 39400-S10-003,39400-SR3-003	This Main Relay Conversion Kit is perfect for Honda and Acura owners who want to stop starting problems and make their car more reliable. It is easy to install and fits many models from 1990 to 2005.	View on Amazon (paid link)
DVPARTS Main Relay Conversion kit 39400-SH3-003 RZ-0063 for Honda	This DVPARTS Main Relay Conversion Kit is perfect for Honda owners who need a reliable replacement part. It’s easy to install and works great for older Honda models like the Civic, CRX, Integra, Legend, Vigor, Accord, and Prelude.	View on Amazon (paid link)
Main Relay Conversion Kit 39400-S10-003 Fit for Honda Civic CRV Integra	This Main Relay Conversion Kit is perfect for Honda and Acura owners who want better starting performance and reliable electrical systems. It’s easy to install and works great for older models like the Civic, CRV, and Integra.	View on Amazon (paid link)
EATAKWARD Main Relay Conversion Kit, Replacement for Honda Accord Civic 1992-2001, Replacement for Honda CR-V Integra 1994-2001	This EATAKWARD Main Relay Conversion Kit is perfect for Honda owners who want a reliable and easy fix for their car’s start-up problems. It’s great for DIYers looking for a simple, plug-and-play solution.	View on Amazon (paid link)
Main Relay Conversion Kit Fit for Civic/CRX 1988-1990, for Integra 1986-1993, for Legend 1986-1990, for Vigor 1992-1994, for Accord 1986-1989, for Prelude 1985-1991	This Main Relay Conversion Kit is perfect for car owners who want to keep their older Honda running smoothly. It’s easy to install and fixes electrical issues that cause engine stalls.	View on Amazon (paid link)

Detailed Reviews

Top main relay kits help your car start fast. These good parts last a long time. Buy the best kit for your car now.

1. Farpida Main Relay Conversion Kit with Kill Switch fit for Honda Civic 1992-2001,CRV 1997-2001, Integra 1994-2001, Accord 1990-2002, Prelude 1992-2001

Farpida Main Relay Conversion Kit with Kill Switch fit for Honda Civic 1992-2001,CRV 1997-2001, Integra 1994-2001, Accord 1990-2002, Prelude 1992-2001

Fix your starting issues fast. This kit replaces faulty main relays with ease. It keeps your car running smooth every day.

It fits Honda Civic, Accord, and CRV models. You get an integrated kill switch for extra safety.

Installation takes just a few simple steps. High quality copper ensures strong power and durability.

Pros	Cons
Fits multiple Honda models, ensuring wide compatibility. Easy installation, direct replacement, ready to use. High-quality materials for reliability and durability. 24/7 customer service for hassle-free support.	Fit may not work on all models. Install may still need care and tools. Kills switch can add extra wiring.

Perfect For:

This kit is for Honda and Acura owners. It stops car theft and fixes start issues fast.

Ready to Purchase?

View Price on Amazon (paid link)

2. Main Relay Conversion Kit Compatible with 92-01 Civic, 94-01 Integra, 97-01 CRV, 93-97 Delsol, 90-02 Accord, 97-99 A cura Cl, 95-98 A cura Tl, 92-01 Prelude

This Main Relay Conversion Kit is compatible with many Honda and Acura models. It works with Civic, Integra, CRV, and more. Check your car’s model before buying.

Installation is plug-and-play. Just replace the factory relay with this one. Add the kill switch for extra security.

The kit uses high-quality materials for durability. It includes a reliable Bosch relay and a 6FT kill switch.

Pros	Cons
Plug-and-play installation—no tools or expertise needed. Widely compatible with Honda and Acura models. Built-in kill switch for added security and peace of mind. High-quality materials ensure durability and reliable performance.	May not fit all trim levels Kill switch needs careful hiding Short cord for some setups

Perfect For:

This Main Relay Conversion Kit is perfect for car owners who want a reliable and easy upgrade. It’s great for those with older Honda or Acura models looking to improve performance and add security with a simple plug-and-play installation.

Ready to Purchase?

View Price on Amazon (paid link)

3. ZUDKSUY RZ-0063 Main Relay Conversion Kit, Replacement for Honda Civic/CRX 1988-1991, Replacement for Acura Integra 1986-1993, Replaces 39400-SH3-003

ZUDKSUY RZ-0063 Main Relay Conversion Kit, Replacement for Honda Civic/CRX 1988-1991, Replacement for Acura Integra 1986-1993, Replaces 39400-SH3-003

The ZUDKSUY RZ-0063 Main Relay Conversion Kit is a perfect fit for many Honda and Acura models. It works with Civic, CRX, Prelude, Integra, Legend, and Vigor. Check your car’s year to be sure it fits.

This kit is built to last with strong materials. The relay switch and mounting bracket handle daily use. It’s a reliable upgrade for your vehicle.

Installing this kit is quick and easy. Just plug it in and replace the old relay. It boosts fuel efficiency and improves engine performance.

Pros	Cons
Fits multiple Honda and Acura models, 1985-1994. Replaces RZ-0063, 39400-SH3-003 with easy plug-and-play. Built tough for long-lasting daily driving performance. Boosts fuel efficiency, improves engine performance. Quick install, no vehicle mods needed.	Will not fit new car plugs. Only fits some old cars. Does not work on new types.

Perfect For:

This is best for Honda car folks who need a quick fix. It will keep your ride top notch.

Ready to Purchase?

View Price on Amazon (paid link)

4. 39400-SH3-003 RZ-0063 Main Relay Conversion kit Compatible with 88-91 Civic/CRX, 86-93 Integra, 86-90 Legend, 92-94 Vigor, 86-89 Accord, 85-91 Prelude,XYgdhqpt

39400-SH3-003 RZ-0063 Main Relay Conversion kit Compatible with 88-91 Civic/CRX, 86-93 Integra, 86-90 Legend, 92-94 Vigor, 86-89 Accord, 85-91 Prelude,XYgdhqpt

The 39400-SH3-003 RZ-0063 Main Relay Conversion Kit is a simple solution for updating your Honda or Acura’s main relay. It works with 88-91 Civic/CRX, 86-93 Integra, 86-90 Legend, 92-94 Vigor, 86-89 Accord, and 85-91 Prelude.

This kit converts your old main relay to a standard relay switch. It includes a relay switch, mounting bracket, and conversion harness. Installation is plug-and-play, with no modifications needed.

Pros	Cons
Compatible with many Honda and Acura models. Easy plug-and-play installation, no changes needed. Includes mounting bracket and conversion harness. Converts old relay to a standard relay switch. Fits vehicles with OBD0 plug for wide use.	Not universal: Only fits specific Honda/Acura models. No instructions: Installation may confuse first-time users. Verification needed: Must confirm compatibility before buying.

Perfect For:

This Main Relay Conversion Kit is perfect for Honda/Acura owners who need a simple, plug-and-play solution to replace their old main relay. It’s ideal for DIY enthusiasts looking for a direct fit with no modifications required.

Ready to Purchase?

View Price on Amazon (paid link)

5. Vkinman Main Relay Conversion Kit with Kill Switch, Replacement for Honda Civic CR-V Accord Prelude 1990-2002, Acura Integra CL TL 1994-2001

Fix your car fast. This kit works well.

It fits your Honda. It fits your Acura. Get new parts now.

Use the kill switch. Keep your car safe. Buy this kit today.

Pros	Cons
Fits perfectly with many Honda and Acura models. Plug and play for a fast, easy fix. Built-in kill switch boosts your car’s security. Reliable relay ensures smooth, stable operation. Simple installation saves you time and effort.	Not for newer models, only older Honda/Acura cars. Kill switch needs smart hiding for best theft protection. No warranty info, so buy with caution.

Perfect For:

This Vkinman Main Relay Conversion Kit is perfect for Honda and Acura owners who want a simple, reliable upgrade. It’s easy to install and adds extra security with a built-in kill switch.

Ready to Purchase?

View Price on Amazon (paid link)

6. XYgdhqpt Main Relay Conversion Kit for Compatible with 92-01 Civic,94-01 Integra,97-01Crv,90-02 Accord,Main Relay Harness 39400-S10-003,39400-SR3-003

XYgdhqpt Main Relay Conversion Kit for Compatible with 92-01 Civic,94-01 Integra,97-01Crv,90-02 Accord,Main Relay Harness 39400-S10-003,39400-SR3-003

The XYgdhqpt Main Relay Conversion Kit is a must-have upgrade for Honda and Acura owners. It fixes common starting problems caused by faulty main relays.

This kit fits many models, including Civic, Accord, CRV, and more. It comes with a standard relay switch and a conversion harness.

Made from durable materials, it ensures reliable performance. Installation is easy, with a plug-and-play design. It enhances driving safety and prevents electrical issues.

Pros	Cons
Fits most Honda and Acura models with OBD1 and OBD2 plugs. Durable materials ensure long-lasting and reliable performance. Easy installation with plug-and-play design. Prevents common starting problems from failing relays. Boosts electrical reliability and vehicle safety.	May not fit all Honda/Acura models perfectly Requires basic knowledge for installation Limited to vehicles with OBD1 and OBD2 plugs only

Perfect For:

This Main Relay Conversion Kit is perfect for Honda and Acura owners who want to stop starting problems and make their car more reliable. It is easy to install and fits many models from 1990 to 2005.

Ready to Purchase?

View Price on Amazon (paid link)

7. DVPARTS Main Relay Conversion kit 39400-SH3-003 RZ-0063 for Honda

This main relay kit is built to keep your ride strong. It fits well. It works fast. It lasts long.

It matches key Honda models from many years. It gives steady 14V 40A power.

This part is new and made with care. It offers high quality. It delivers good service every time.

Pros	Cons
Fits your car with no stress. Easy to plug in and run. Starts your car fast each time. Built strong to last long. Great quality you can trust.	Only fits old cars. Needs hand work to set up. Will not fit new cars.

Perfect For:

This DVPARTS Main Relay Conversion Kit is perfect for Honda owners who need a reliable replacement part. It’s easy to install and works great for older Honda models like the Civic, CRX, Integra, Legend, Vigor, Accord, and Prelude.

Ready to Purchase?

View Price on Amazon (paid link)

8. Main Relay Conversion Kit 39400-S10-003 Fit for Honda Civic CRV Integra

Fix your car with this new kit. It helps your car start fast every time.

Just plug it in to save time. The strong parts will last long. Stop car problems and drive smooth.

Pros	Cons
Boosts starting power for reliable car ignition. Upgrades electrical system, cuts breakdowns. Fits multiple Honda/Acura models perfectly. Durable materials, handles extreme conditions. Easy DIY install, saves time and money.	Not for newer car models. Requires removing old factory relay. Limited to select Honda and Acura vehicles.

Perfect For:

This Main Relay Conversion Kit is perfect for Honda and Acura owners who want better starting performance and reliable electrical systems. It’s easy to install and works great for older models like the Civic, CRV, and Integra.

Ready to Purchase?

View Price on Amazon (paid link)

9. EATAKWARD Main Relay Conversion Kit, Replacement for Honda Accord Civic 1992-2001, Replacement for Honda CR-V Integra 1994-2001

The EATAKWARD Main Relay Conversion Kit is a perfect replacement for Honda models from 1992 to 2001. It fits Accord, Civic, CR-V, and Integra, ensuring a seamless upgrade.

This kit offers easy installation, reliable performance, and improved circuit stability. It comes with everything you need, ready to use right out of the box.

Pros	Cons
Fits perfectly with multiple Honda models from 1992 to 2001. Easy plug-and-play installation, no special tools needed. Boosts circuit stability to reduce start-up issues. Tested for reliability in daily driving conditions. Complete kit includes everything shown in the picture.	Limited to specific Honda models from 1992-2001 only Installation may still require basic car knowledge Does not include detailed installation instructions

Perfect For:

This EATAKWARD Main Relay Conversion Kit is perfect for Honda owners who want a reliable and easy fix for their car’s start-up problems. It’s great for DIYers looking for a simple, plug-and-play solution.

Ready to Purchase?

View Price on Amazon (paid link)

10. Main Relay Conversion Kit Fit for Civic/CRX 1988-1990, for Integra 1986-1993, for Legend 1986-1990, for Vigor 1992-1994, for Accord 1986-1989, for Prelude 1985-1991

Main Relay Conversion Kit Fit for Civic/CRX 1988-1990, for Integra 1986-1993, for Legend 1986-1990, for Vigor 1992-1994, for Accord 1986-1989, for Prelude 1985-1991

This kit fits many Honda cars. It replaces old parts for a better ride. You will love the quality.

The metal is very strong. It stays stable in bad weather.

The plug is very easy to use. It stops the engine from stalls. Your car will run very well.

Pros	Cons
Fits multiple models, ensuring wide compatibility for your vehicle. High-quality materials guarantee durability and reliable performance. Easy plug-and-play installation saves time and effort. Prevents engine stalls, keeping your drive smooth and efficient.	Not universal: Only fits specific Honda models from the 1980s-1990s. No DIY for beginners: Requires basic wiring knowledge for proper installation. Limited upgrade: Doesn’t enhance performance, just fixes electrical issues.

Perfect For:

This Main Relay Conversion Kit is perfect for car owners who want to keep their older Honda running smoothly. It’s easy to install and fixes electrical issues that cause engine stalls.

Ready to Purchase?

View Price on Amazon (paid link)

Buying Guide

You want a smooth start, a steady engine, and a safe drive. A good main relay conversion kit helps you get all three. It makes your car feel strong, stable, and ready every day.

Factors to Consider When Buying a Main Relay Conversion Kit

Compatibility: Make sure the kit fits your car’s year and model. Check the part numbers. A correct match gives you fast starts and steady power.
Build Quality: Look for strong metal and solid copper parts. Good materials last longer. They keep your electrical system stable.
Relay Type: Some kits use a Bosch-style relay. Others use a standard relay switch. Pick the type your car responds to best. Both can give smooth performance.
Harness Design: A good conversion harness makes setup easy. It should fit tight. It should stay secure. This helps your car run clean and steady.
Kill Switch Option: Some kits include a kill switch. It adds extra control. It keeps your car safe when parked.
Ease of Installation: Choose a plug-and-play kit. It saves time. It avoids stress. You get your car running fast again.
Durability: Look for kits made with strong parts that resist heat. They stay stable in tough weather. They keep your car running smooth.
Performance Boost: A good kit can improve fuel flow and engine response. It helps your car start quick. It keeps your drive steady.
Brand Reliability: Pick brands known for quality and long life. Trusted makers give you better support. They offer strong parts that last.
Price vs Value: A fair price is good. But value matters more. Choose a kit that gives long life, easy setup, and steady power.