Fans won't turn off

Why do the fans stay on changed temp senser and thermostat but they just stay on any ideas

Did they used to do it or is this a new problem

No didn't do it before

You got aircon button pressed on ?

Air on removed button not switched on

Relay sticking ? Is it clicking as you turn ignition on and off ?

got the same problem with mine appear after refitting the engine

sorry to revive a dead tread but anyone got any cures for this issue?

Dodgy air con relay or engine temperature sensor duff?
When you start the car when its cold, does the fast idle stuff work ok?

My car had its AC removed before I bought it and I latterly found out the fans weren't coming on at all. It turned out there's a small two wire plug down the RH side of the rad (while looking from front of car) that I needed to bridge to sort my issue. I don't know what it plugged into but I assume some kind of AC pressure/temperature sensor/switch. Try unplugging it to see if that stops them

Only 3 things that ecu logic uses to command fans on .
1 Coolant temp sensor (2 wire)
2 aircon switched on
3 ecu detected fault and running in safe mode .

could be as simple as ecu coolant sensor faulty or wiring faulty (if disconnected, open circuit or resistance always at hot water value fan always on) .
* this been connected right after engine fitting !? harness or other wirng damaged connected wrong !?
aircon fault or fan relay circuit fault, ecu control circuit fault .
Pretty easy test these circuits and narrow things down.
If you got consult  adaptor you can see what ecu doing and what input value is switching the fans on.
Every owner should have the consult adaptor as was less than 20bucks and obd scan tech nissan software free (see useful link section)
simply testing pin 9 at ecu with DMM (ecu ground switch control for fan relay switch side) will tell you if ecu commanding fans on or if relay stuck on or grounded another way .
Simple checks on coolant sensor another good place start .
Some thread links below with pdf file links and general tips that could help you do diagnosis on this fault if read through them (if simply not wrong plug harness on ecu coolant sensor or similar) .
http://www.gtir-motorsport-club.com/t6996-radiator-fans-refuse-to-kick-in
http://www.gtir-motorsport-club.com/t6965-need-expert-advise-for-start-up-issues