Flex-a-lite Compact Adjustable Electric Fan Controller & Relay Kit — Black, Thread‑in Probe, 160–220°F Range

The Flex-A-Lite Compact Adjustable Electric Fan Controller and Relay Kit is a self-contained 12V switching module with a thread-in temperature probe that automates single or dual electric radiator fan operation between about 160–220°F and forces the fan on when A/C is active.

This compact kit is built to simplify wiring and deliver reliable engine temperature control without separate external relays. Housed electronics are potted for water resistance and vibration protection, and the package includes the relay, inline fuse, wiring, terminals, a thread-in probe with adapter bushings, and room for an optional manual override switch. It’s designed for common automotive installations and supports typical 12‑volt fan circuits.

How does the controller determine when to switch the fan on and off?

The unit uses a temperature probe that threads into a coolant or header port and senses engine temperature. You can adjust the turn-on point across a specified range so the fan comes on only when needed. It also senses A/C engagement and energizes the fan whenever the air conditioning is on to improve condenser performance.

• Adjustable activation range approximately 160–220°F
• Thread-in temperature probe with adapter bushings for 1/4", 3/8", and 1/2" NPT ports
• Automatic A/C input forces fan on for better cooling and condenser efficiency

What wiring and components are included for installation?

The kit arrives with the relay, an inline fuse assembly, wiring harness and electrical terminals sized for standard fan installations. Potted electronics reduce exposure to moisture and vibration, which helps electrical longevity. Provisions for an optional manual override switch are built in so you can add driver control if desired.

• 30‑amp relay and inline fuse installed in harness
• Wiring and terminals for common single- and dual-fan setups
• Space to connect an optional manual override switch for direct control

Which fans and vehicles are compatible with this Flex-A-Lite kit?

Designed for typical automotive electric fans, the controller is suitable for 12‑volt fans drawing up to the kit’s rated current. It handles standard engine cooling and radiator fan applications and can be configured for single or paired fan configurations. Use the included probe bushings to fit most header or block ports for accurate temperature sensing.

• Compatible with 12‑volt automotive fans (check fan current vs. relay rating)
• Works with single- or dual-fan systems when wired per instructions
• Probe adapter bushings fit 1/4", 3/8" and 1/2" NPT threaded ports

Who this is for: The Flex-A-Lite Compact Adjustable Fan Controller is aimed at DIY mechanics, custom builders, and performance enthusiasts who want a compact, integrated fan control solution without adding separate relays. It’s a good choice when you need adjustable temperature activation, automatic A/C-linked fan operation, and a rugged, vibration-resistant module for under-hood service. If your project uses 12V fans within the relay’s capacity and you need an easy-to-install controller with probe flexibility, this kit provides the wiring and hardware to get the job done reliably.