radiator temp switch???

whats up with the single pole temp switch...got a dual fan set with a 40 amp relay and harness and single pole temp switch and no schematic..i realize there is a schematic on the relay but it doesnt say where the wires hook up to...three wires out of the harness ...its confusing....three wires..one (30) power into relay ...(87) should be out to fans(there's a 87a also)....(86) should be ground (85) should be relay source power....seems like there should be another wire off the harness...and does the single pole act as a ground?????????...thanks in advance

 

Bosch relay
Google Bosch relay and it will explain the different ways of using a relay.

 

The relay ground (86) should go the the temp sender instead of directly to ground.

Sorta like this here: