Blue Sea 1821 Universal Temperature Sensor

The Blue Sea 1821 Universal Temperature Sensor is an essential monitoring tool for any serious boater or angler who depends on reliable engine diagnostics. Whether you're running offshore or cruising inland waters, engine temperature management is non-negotiable—overheat at the wrong moment and you're facing catastrophic damage or being stranded miles from the dock.

This compact universal sensor integrates seamlessly into existing Blue Sea Systems electrical architecture, providing real-time temperature data at a glance. Designed for universal compatibility, the 1821 sensor works across multiple engine types and cooling systems, making it ideal for retrofit installations or new builds.

Experienced captains and mechanics trust this sensor because it delivers consistent, repeatable readings in the harsh saltwater and freshwater environments where marine engines operate. Installation is straightforward—most applications require only basic plumbing skills and a standard wrench, ensuring that you can easily upgrade or replace your existing temperature monitoring system.