Keystone Side Marker Light Assembly

The Keystone Thermal Disk Switch Cooling Fan Temperature Sensor is a replacement cooling fan temperature switch, also called a fan thermostat switch or radiator fan sensor. It monitors engine coolant temperature and signals the electric cooling fan to turn on when the engine needs more airflow. This helps the engine stay in its normal operating temperature range.

Key Features:

• Thermal disk switch design that reacts to changes in coolant temperature
• Turns the electric radiator cooling fan on and off automatically
• Helps prevent overheating in traffic, at idle, and under load
• Made as a direct replacement for the original-equipment switch
• Available under individual part numbers, so you can choose the one that matches your application

A worn or failed fan temperature switch can cause the fan to run constantly, run late, or not run at all. Replacing it restores proper fan control and helps protect the cooling system and engine. Keystone Automotive Industries is known for OEM-style replacement parts, and this switch follows that approach, offering a dependable repair part for routine cooling system service.