GDUKOP Dual-Speed Wiring Harness Kit for Chevy/GMC V8s — 674-00923 with Relay & Weatherproof Connectors

The GDUKOP 674-00923 wiring harness kit is a complete dual-speed electric fan control solution with relays and weatherproof connectors made to OE-fit standards for Chevy, GMC and Cadillac V8 cooling systems.

This harness assembly is built to replace or upgrade the factory fan wiring for vehicles that use 34-inch radiators and dual electric fans. It combines relays, fuses, sockets and automotive-grade wiring into a self-contained loom engineered to support both low- and high-speed fan operation. The kit is intended to simplify installation while improving reliability in high-heat engine bays and when retrofitting aftermarket fans.

How does this harness manage low and high fan speeds?

The kit uses separate relay paths and a dedicated wiring layout to switch fans between low and high speeds according to the vehicle’s cooling signals. This prevents crossed circuits and delivers reliable power to the fan motors under variable cooling demand.

• Dual-relay design separates low-speed and high-speed circuits for dependable switching.
• Pre-wired connectors match common fan plug types used on Chevy/GMC/Cadillac models.
• Includes inline fuse protection to safeguard fan motors and wiring.
• Wiring and terminals pre-tested to OE-style electrical tolerances.

Will this fit my truck or SUV?

The harness is engineered for a specific group of GM models and radiator sizes; it’s tailored for vehicles that originally used dual electric fans with 34-inch radiators. Before purchasing, compare connector types and the vehicle list to ensure compatibility.

• Compatible models include Chevrolet Silverado 1500/2500 Classic, Avalanche 1500/2500, Suburban 1500/2500.
• Also fits GMC Sierra 1500/2500/3500 Classic, Yukon and Cadillac Escalade EXT/ESV where dual-fan setups are used.
• Check the photos (Main Image 7 and 8) for pin layouts and mounting points if unsure.
• Designed for 34-inch radiator applications—verify radiator width before ordering.

How durable and weatherproof is the kit for engine bay use?

GDUKOP built the harness from automotive-grade, heat-resistant wiring and weather-sealed connectors to withstand the heat, moisture, and vibration found under the hood. The relay sockets and terminals are prepared for repeated use and long-term exposure to automotive operating conditions.

• Heat-resistant insulation protects conductors in high-temperature zones.
• Weatherproof plugs and sealed terminals reduce corrosion risk.
• Relays and fuse holders are mounted to minimize stress from engine vibrations.
• Each wire and terminal is factory-tested for continuity and fitment.

What comes in the box and how simple is the installation?

The kit ships as a stand-alone wiring assembly with relays, fuses and connectors pre-assembled for a straightforward swap or retrofit. Basic hand tools and a wiring diagram are typically all that’s needed; some models may require tying into existing chassis ground or trigger wires.

• Complete wiring loom with two relays, fused power feed, and fan connectors.
• Pre-crimped terminals and sealed connector housings for plug-and-play fitment.
• Instructions and reference photos included—see Main Image 7 and 8 for wiring pinouts.
• Designed for quick replacement of OEM fan harnesses or integration with aftermarket fans.

Who is this for: This GDUKOP 674-00923 kit is aimed at owners and technicians working on late-model GM trucks and SUVs that employ dual electric fans and 34-inch radiators. It suits anyone replacing a failed factory harness, upgrading cooling for towing or heavy loads, or installing aftermarket fans while retaining correct low/high-speed control. If you need OE-form fitment, robust heat resistance and a complete relay-based wiring solution, this harness provides a ready-made option that reduces fabrication time and improves electrical reliability.