ZOZOMOTORS Dual Electric Fan Relay Kit 40A with 185°F On/175°F Off Temp Switch — Labeled Harness & 3/8" Thread Adapter

This ZOZOMOTORS Dual Electric Fan Relay Kit is a complete 40A wiring and temperature-switch solution that automatically runs two medium/low-profile cooling fans when coolant reaches about 185°F and stops them near 175°F.

This kit bundles a 40 amp relay, an OE-style temperature switch, and a labeled wiring harness so you can add or replace an electric cooling fan system quickly and reliably. All wires are color-coded and marked, the package includes a clear wiring diagram, and the temperature sensor ships with a 3/8" thread plus a 1/2" adapter for flexible mounting. It’s designed as a direct-fit replacement for many 10", 12", 14" and 16" fans and is intended to control two medium or low profile fans safely.

How does the temperature switch decide when to run the fans?

The included OE-style temperature switch closes at approximately 185°F and opens around 175°F, triggering the relay to power the fans only while coolant is above the set threshold. It must be screwed into a grounded metal surface (engine or water jacket) to function properly.

• Switch activation: ~185°F on, ~175°F off.
• Thread: 3/8" with a supplied 1/2" adapter for alternate fittings.
• Requires engine grounding through the sensor threads for correct operation.
• Use with a thermostat rated at 160°F or lower for correct cycling.

What electrical parts and wiring are included, and how do they help installation?

This kit contains everything needed for a tidy, safe install: a 40A relay, labeled harness, inline waterproof fuse holder with fuses, ring terminals, and connectors. Wires are color-coded and marked to match the included wiring diagram, reducing installation errors and time.

• Red lead: 12V positive battery feed.
• Coffee-colored lead: fan positive output to fans.
• Black lead: connection to the temperature sending unit.
• Grey lead: ignition-switched input per diagram.
• Accessories: 8 ring terminals, spade for sensor, 4 wire connectors, and fuses.

Can this kit handle any fan type and what are the wiring limits?

The 40A relay and wiring supplied are sized to run two medium-profile or low-profile fans. High-profile or very high-current fans may overload the harness unless you upgrade wiring or use the heavy-duty ZOZOMOTORS relay kit P/N 30247.

• Designed for two medium/low-profile fans on 40 amps total.
• For high-profile fans, use model 30247 or larger gauge wires for pins 30 and 87.
• If modifying, crimp/solder 10 AWG wire for higher current capacity per fan.
• Always protect battery feed with the supplied inline fuse.

How do I avoid installation or operating mistakes?

Follow the color-coded wiring diagram included and ensure the temperature switch threads make solid metal contact with a grounded engine surface. Match your thermostat rating to the switch’s trip point for predictable cycling.

• Install the sensor so its threads are grounded to the engine block or water jacket.
• Use a 160°F thermostat (or lower) with this 185°F switch for correct on/off behavior.
• Check fuse rating and wiring gauge before powering the fans.
• Label and secure wiring away from hot or moving parts for longevity.

Who is this for: The ZOZOMOTORS Dual 40A Electric Fan Relay Kit is built for DIY mechanics, performance enthusiasts, and professional installers who need a straightforward replacement or upgrade for electric cooling fans on cars, trucks, and custom builds. It suits vehicles using one or two medium or low profile fans where automation, reliable wiring, and an OE-style sensor are required. If you plan to run large high-profile fans, consider the heavy-duty relay option or upgrade wiring to match higher current needs.