Fan of NC30 issue

[phlymo]

The bike overheats, so i replaced the switch thinking this was the problem, as the fan was not coming on. I have now connected it to a radiator bolt and it now is permanently on, when the ignition is on. Solved the overheating issue, but worried that this will kill the battery. If i push the cable directly onto the radiator, the fan does not come on. Any ideas what could be the problem.

[phil x]

The fan needs earth to run, this is what the fan switch does when up to temp.
If the fan comes on when you earth the wire, the circuit & motor are working correctly.
If the fan doesn't work when you 'earth' the wire to the radiator, then the radiator isn't earthed. They are rubber mounted & should have an earth wire from the rad to the bikes frame/engine/battery or wherever. you may have a loose earth wire dangling that has not been reconnected or corroded off or just have a bad connection

Phil

[phlymo]

Phil, thank you. This all makes sense now. I will have a look over the weekend.