There are two sensors, the engine coolant temperature sensor is on the front of the right intake manifold. The sending unit is located under the thermostat housing on top of the engine case. I believe that the sending unit is the one thatdrives the temperature gauge. The engine coolant temperature sensoris for the ECU, I believe.The thermostat switch is under the left radiator. Think this the one that controls the fans. My Clymer manual is out in the shop and it's raining right now or I'd go check on that for sure.I own a GL 1500 1996. My fans do not go on. I checked out fans they are in working order. My question is what causes the fans to go on after engine heats up? Is it the engine coolant temperature sensor?