Overheating problem

[pbergin]

The overheat light comes on not long after I start the bike. I've replaced the fan switch, the thermostat and the heat sensor for the light. The temps at the head, and both the inflow and outflow to the radiator are all normal. The fan turns on and off at exactly the correct temperatures. I'm stumped!

Has anyone seen this before, and have an answer?

[WintrSol]

The temperature gauge (sender) is wired directly to the circuit in the 'dash' that measures its value to ground. That circuit has a direct wire to the engine, so other things that connect through ground, like turn signals, don't disturb it. When the value of the gauge drops to about 17 Ohms, the light comes on, so any leak to ground on the wire (B/G) that connects it to the circuit will cause it to light prematurely. The ground wire (B/Br) connection to the engine could also be corroded, making it appear the resistance is low. Or, the circuit has failed.