[TStiles]

The single-pole sender provides variable resistance as the temperature rises and falls, thus sends the reading to your gauge. The two-pole sender is an on/off unit which when closed, is a pass-through device, sending the resistance feed from the single-pole sender on to the gauge. When it senses an overheat condition, it goes open, breaks the circuit, and the gauge will indicate full-on hot. Kinda Mickey Mouse, but it works pretty well on a motor with two separate cooling systems. An alternative is to install two of the single pole sensors and a L/R switch so each head can be individually monitored. Or use a dual readout gauge and senders from someone like Westach.