Pesario 910US overheating

I have a compaq 910 laptop that overheated and toasted the cpu. Upon reinstalling a new board the heat sink fan works. but the exhaust fan coming off the back of the laptop doesn’t. I have hooked other fans up, I have also hooked a PSU up to each fan to insure they are working. I relize this fan might be temperature controlled, but its still not kicking on because my laptop is over heating and shutting down.