Spal 185TS One Wire 185 Degree Thermoswitch For Radiator Or Oil Cooler Fans 3/8" NPT Pipe Thread

The 185TS single wire thermal switch turns the fan on at a temperature of 185 degrees and off at 165 degrees. It is 3/8" NPT pipe thread. Spal also offers a two wire version of this sending unit if you're having trouble getting the sender to ground because of Teflon tape or pipe sealant. The two wire sender gives you the ability to ground directly to any chassis grounding location versus trying to obtain a ground through the engine.

The thermostat switch acts as a ground for a relay. As the thermostat reaches the appropriate temperature it completes the ground circuit for the fan relay, then activates your radiator or oil cooler fans.