Spal 40A Fan Harness with Relay — Universal 12V Wiring Kit, Fused Battery Lead

Spal's 40 Amp Fan Harness with Relay is a ready-to-install wiring kit that lets you control a high-current electric fan safely and reliably.

Designed for universal fit applications, this pre-assembled harness from Spal simplifies wiring an electric cooling fan, replacing homemade splices and fragile inline switches. The kit routes power through a heavy-duty 40 amp relay and includes the connectors and mounting points needed to integrate with most aftermarket and factory fans. It reduces strain on existing wiring, protects switches from burnout, and helps ensure consistent fan operation under load.

How does this harness protect my vehicle's electrical system?

The harness routes high current through a dedicated 40 amp relay so the fan draws power directly from the battery rather than through a dash switch or fragile factory wiring. That prevents overheating of thin wires and reduces voltage drop at high fan speeds. The result is safer operation and longer component life.

• 40 amp relay carries heavy loads without overheating
• Direct battery feed minimizes voltage drop
• Plug-and-play connectors reduce risky wire splices
• Pre-mounted relay simplifies secure installation

What components are included and how easy is it to install?

The harness comes pre-assembled with the relay, fused power lead, ground wire, and factory-style connectors to mate with many electric fans. Installation typically requires mounting the relay, connecting the fused power lead to the battery, grounding the harness, and plugging the fan connector into the fan motor. Basic hand tools and a multimeter are recommended for a safe, correct fit.

• Pre-wired relay with mounting tab for easy attachment
• Fused battery lead for overload protection
• Ground lead and compatible fan connector included
• Universal fit design works with most aftermarket fans

Will this harness work with my fan and vehicle type?

Spal's universal harness is built to accommodate a wide range of 12V electric fans used in cars, trucks, and performance builds. Confirm connector compatibility and ensure your fan's current draw does not exceed 40 amps. If your application draws near or above 40A continuous, consider a higher-capacity relay or dual-relay setup.

• Universal fit for most 12V electric fans
• Designed for applications under 40 amps continuous draw
• Check connector pin layout for exact match
• Works in cars, light trucks, and custom builds

Does the harness include safety features and specifications?

The wiring kit includes a fused power lead and a heavy-duty relay to reduce the risk of electrical faults. Package dimensions and weight make it compact for storage and shipping. The harness is produced in China to Spal's quality standards and is intended for automotive use only.

• Includes inline fuse on battery feed for added protection
• 40 amp relay rated for high-current switching duties
• Compact package dimensions for easy stowage and shipment
• Manufactured to Spal's production specifications

Who is this for? Technicians, DIY enthusiasts, and performance builders who want a reliable, ready-made wiring solution for electric cooling fans will benefit from Spal's 40 Amp fan harness. It's ideal when upgrading to a high-flow aftermarket fan, replacing a worn factory harness, or adding an electric fan to a radiator conversion. If you need a straightforward, serviceable harness that cuts installation time and reduces electrical risk, this kit is a practical choice.