overheating issues

hey guys. atv in question is a 2003 kodiak 450. i recently rebuilt its engine and have been riding it a bit. when the engine gets hot the fan never comes on. however when you turn off the ignition key the fan will come on (only once it is hot). the fan comes on before the overheat light will but again only when the ignition is off. if the engine is kept running the fan will never come on despite being overheated. so i know the fan works, and the radiator temp switch was probably fine but i replaced it anyway and saw no change. fan circuit breaker is okay too. obviously the fan itself works. when you turn off the ignition the fan will run until the temp switch cools off. the temp switch on the cylinder head is just an inducator light as far as i know but it is good too. i bridged the pins on the temo switch plug and still the fan does not come on.

any advice would be appreciated. i am probably going to cut into the harness and wire a toggle switch directly into the radiator fan if i cannot find the issue.