Working on a complete re-wiring of a friend's converted quad bike/atv with a KTM 640 LC4 engine (he bought used).

I'm unsure where the radiator on this bike has come from and can't read any markings on it as they've been scratched off.

Took the Thermo switch from bottom of radiator to test and get no continuity between the pins when the sensor is placed in hot water or when heated directly. Get no resistance changes either even tried putting over flame for a while and nothing.

Believe this is a fan switch, can make out a few markings on the back of the switch:
75C
J04

I've included images as unsure what top line says.

I measured with calipers:

• 9.6mm diameter for thread
• 0.5mm pitch (measured from peak to peak?)
• 14mm between terminals

I've looked at a few places online but can only find temperature senders for gauges and not temperature switches.

On the top of the KTM 640 there's a temperature wire that should go to gauge, is it possible to use this one to switch a fan?

If anybody could advise on a replacement or a way around that doesn't involve a manually switched fan that would be great.

 

A thermoswitch switches power or vacuum when a certain temp is reached. A coolant temp sensor just reports the temperature. It's up to the computer to decide when/what to switch.