Maernz 40A Dual Electric Fan Relay Kit – Engineered for peak performance and reliability in demanding automotive environments. This complete kit features a precision-engineered 185°F/175°F thermostat that activates cooling fans at 185°F and shuts them off at 175°F, maintaining optimal engine temperature with a 10°F differential (narrower than industry standards) to prevent overheating and reduce wear. The 40A heavy-duty waterproof relay powers dual mid/low-profile fans effortlessly, backed by flame-retardant silicone wiring (125°C rated) and self-resetting fuses for ultimate safety in trucks, SUVs, or RVs.
Designed for DIY simplicity, its color-coded wiring harness (RED=12V+, COFFEE=Fan+, BLACK=Sensor, GREY=Ignition) and pre-crimped terminals enable a 15-minute installation—no extra tools required. The OE-style 3/8" NPT sensor (with 1/2" adapter) threads directly into engine blocks, while strict grounding via sensor threads ensures accurate operation (test with multimeter post-install).
Pro Tip: Pair exclusively with a 160°F thermostat (incompatible with higher temps like 180°F) to avoid fan overrun. Upgrade to Maernz Heavy-Duty Kit for high-profile fans or rugged off-road use. IP67-rated components and a 2-year warranty guarantee durability.
What's Included:
40A Waterproof Relay
Thermostatic Switch + 3/8" to 1/2" Adapter
Pre-Wired Harness with Inline Fuses
8 Connectors & Installation Guide