HD Relay: H8

The Morimoto HD Relay Harness H40 is engineered to provide your HID lighting system with a clean, stable power supply directly from your vehicle's battery. Factory headlight circuits are designed to power halogen bulbs and often cannot supply the consistent voltage required by HID ballasts. The H40 eliminates voltage drops that can cause flickering, delayed ignition, and unreliable HID performance, ensuring your lighting system operates at its full potential.

Whether you're upgrading your headlights or fog lights, the Morimoto H40 delivers dependable power, improved ballast performance, and long-lasting reliability.

Why Install a Relay Harness?

A relay harness is one of the most important components of any HID conversion. Even the highest-quality HID bulbs and ballasts require a stable power source to perform reliably. By drawing power directly from the battery, the Morimoto H40 improves startup performance, reduces strain on the factory headlight wiring, and helps maximize the lifespan of your HID components.

Benefits

• Faster HID ballast startup
• Consistent light output
• Eliminates headlight flickering
• Improves ballast reliability
• Stable battery voltage for maximum HID performance

Plug-and-Play Installation

The Morimoto H40 features a true plug-and-play design with no cutting or splicing required. Its universal wiring layout and generous wire lengths allow for installation on most passenger cars, trucks, SUVs, and off-road vehicles.

Installation is quick and simple:

• Connect the harness directly to the vehicle battery
• Plug into the factory headlight connector
• Connect your HID ballasts
• Secure the relays and wiring

The result is a clean, professional installation while preserving your factory wiring.

Universal Compatibility

The H40 Relay Harness uses industry-standard ballast connectors, making it compatible with nearly all aftermarket HID lighting systems.

Ideal for:

• HID low beam conversions
• HID high beam conversions
• HID fog light conversions

Please Note: Vehicles equipped with CANBUS electrical systems or pulsed Daytime Running Lights (DRLs) may require a Morimoto CANBUS or Mopar-specific relay harness for proper operation.

Dual Relay Fail-Safe Design

Unlike many generic relay harnesses that rely on a single relay to power both headlights, the Morimoto H40 utilizes dual independent sealed 40A relays, providing one dedicated relay for each headlight. This fail-safe design ensures that if one relay ever fails, the opposite headlight can continue operating for added safety and reliability.

Each relay features:

• Fully sealed weather-resistant housing
• Ribbed silicone weather seals
• Integrated flyback diode for back-EMF protection
• Weatherproof connectors throughout the harness

Designed to withstand moisture, vibration, dirt, road salt, and harsh weather conditions, the H40 is built for years of dependable service.

Premium OEM-Grade Construction

Manufactured using premium automotive-grade materials, the Morimoto H40 offers exceptional durability while maintaining a factory-quality appearance.

Construction features include:

• Heavy-duty automotive wiring
• Abrasion-resistant Techflex braided sleeving
• OEM-style sealed relay housings
• Polished stainless-steel relay mounting bracket
• Weatherproof electrical connectors

The finished installation is clean, organized, and looks right at home under the hood.

Features

• Stable battery power delivered directly to HID ballasts
• Eliminates flickering and unreliable HID startup
• Universal plug-and-play installation
• No cutting or splicing required
• Compatible with most aftermarket HID systems
• Suitable for low beams, high beams, and fog lights
• Dual independent sealed 40A relays
• Flyback diode protection for enhanced electrical reliability
• Premium weatherproof construction
• OEM-quality materials and finish

Package Includes

• 1 × Morimoto HD Relay Harness H40
• Complete plug-and-play HID relay harness for one vehicle

Upgrade your HID lighting system with confidence using the Morimoto HD Relay Harness H40. Built with premium materials and engineered for dependable performance, it provides the stable power, durability, and OEM-quality construction needed for virtually any HID headlight or fog light conversion.