I have no experience with scooters like yours, but all radiator fans basically work the same. Therefore it should not be too difficult to trace the problem. The problem can be caused by:
1. A blown fuse.
2. Loose or broken wires, or bad / corroded wire connections.
3. Faulty thermal Switch.
4. Faulty Relay (probably used on scooters like yours).
5. Faulty fan motor.
I would look for a blown fuse first, and if all fuses are okay, I would:
- disconnect the loom to the fan motor at the thermal switch.
- switch the ignition key on, but do not start the engine.
-do a Voltage test at the wires previously connected to the thermal switch. You should get a 12 Volt reading at one of those wires. If not, the scooter could be wired differently
and you should get a 12 Volt reading at another wire which connects to the fan Motor.
- If you managed to find a 12 Volt reading, it means:
1. The fuse is not blown.
2. The wires and connections before the thermal switch are fine.
3. The relay (if any) COULD be fine (depending on how it's been linked to the fan motor).
4. The thermal Switch could be faulty.
5. The fan Motor could be faulty.
To know whether the thermal switch is faulty or not, I would test the fan motor first by doing the following:
1. Link the Positive (+) wire on the loom to the fan Motor with an external wire directly to the battery, with a fuse in between.
2. Link the Negative (-) wire on the loom to the fan Motor (or however (-) gets connected to the fan) directly to the (-) on the battery.
If the fan is running, chances are about 100% that you are having a faulty thermal Switch - or a faulty Relay (if relays are used on scooters like yours).
If you couldn't get the fan motor running - it obviously means the fan Motor is faulty.
Good luck. Again, have no knowledge about scooters like yours - but I think it shouldn't be too difficult to trace the problem.
P.S. If the manufacturer didn't use Relays at fan motors on scooters like yours - one of the first things I would do is to do a relay modification to the fan motor. By saying this I might become very unpopular - but I find it difficult to understand how a fan motor would be reliable without a relay linked to the system. Specially when the fan works hard during very hot conditions.
