Fan won't go on
 

I have a SYM HD200
It is water cooled.
There is a fan in front of the radiator, it is turned on by a thermal sensor that is screwed into the radiator.
So the fan does not come on when the scoot gets hot. It should enable at about 210 degrees F
I pulled the two wires, and jumping them together turns the fan on.
I replaced the sensor with a known good sensor.
No joy, fan does not come on.

So the only thing I can figure out is the fluid in the radiator is not hot enough because:

Air in system (was professionally flushed last month at a dealer)
Thermostat not opening
Water pump not working.

Anything else anyone can think of? I will test the thermo tomorrow by taking off the cap and cranking it up. You can see when the thermo opens.

Any other ideas?

Is there a relay that the sensor sends a signal to? You might want to check the good sensor for continuity in hot water somehow too. Maybe attach test leads to the sensor.

Fixed. Both switches were bad. Installed one of these, fan pops on a 190F and keep the engine nice and cool:

http://www.ebay.com/itm/261235617604