so i have a 1997 Ls 3.1L and recently my fans have not been turning on and during IDLE it results
in overheating, ive checked my relays, checked my temp sens. and volt met. everything and i am getting power to the relays and sensor, but still no luck.also i got the fans to turn on by taking the temp sensor out and putting it back in but after turning the car off and on the fans not working again

Im alittle stumped on this, would it be something with the pcm or a thermostat? or something else?
thanks

 

Have you checked the conections on your fan assembly? Occasionally the connections will become loose and work for alittle bit. Or it could be your T-Stat have a problem and not allowing coolant to flow which is telling your car "Hey! Im still cold, no need to turn on the fans!"

 

Im curious to as to where is your temperature guage when you say its overheating. I though the same thing about my car but its just with in normal operating range. The temperature for the fans to come on i want to say is 21x* Thermostat opening at 195*. Someone correct me if im wrong...

 

Try your under hood fan fuse.