Cooling fan will not kick on when warmed up but if you unplug the sensor it will work

have you bothered to check the thermal fan switch...

if you unlplugged the temp sensor so the fans will run the cars computer cant read engine temp and will call for to much fuel which will run good when cold but bad when warmed up

I’m happy to assist further over the phone at https://www.6ya.com/expert/joe_a3369546f8067589

Does it work when you turn the A/C on? The fan always kicks on with the A/C, if it doesn't look for a blown fuse. Or possibly a fan motor burnt up. If it works with the A/C but doesn't when the engine is too warm, it is probably the temperature sensor.

COOLING FANS NOT RUNNING

It is normal for the A/C air to warm up a little when stopped. Less airflow thru the condensor. It is normal for the engine temperature gage to rise up to about the 80% mark on its scale before the cooling fan kicks on. The gage will also show about the same reading on the first start of the day, until the thermostat opens.

If the fan(s) are not working properly the A/C air and engine temperature will rise. If you have a belt driven clutch fan, the clutch may be worn out. All cooling fans kinda sound like miniature jet engines when its hot out, more so when the A/C is on. Replacing the clutch is all you can do for a belt driven fan. Electric fans are more complicated....
Check all main power electrical connections first.... Electric Fan(s) not working, Checking the fan(s), relay, fuse and engine temperature sensor's.
Verify that the fans work by unplugging them and run jumper wires to the fan(s) from the battery. If they run, your problem lies elsewhere. If either does not run, it's the motor.
Next thing to check is for power at the fan connectors. You have to be cautious doing this because the engine needs to be running and warm if not almost hot, and the A/C also needs to be on. (Both must be on and running for the duration of this checklist.) The A/C fan is on the passenger side and should come on almost the instant the A/C is turned on. It is also the secondary engine cooling fan and should cycle on and off in relation to engine temperature. Use a test light to probe the two wires on each fan. If you find power the fan motor(s) is/are probably bad. If there is no power to fans, roll up your sleeves!

The temperature switch is usually located above the oil filter. If the dash gage is working, its probably OK. Next is the Fan Control Temperature Sensor, located IN or CLOSE to the thermostat housing. You will find out if it is working later is this checklist. I just wanted you to know where it is. Next is the relays and fuse's. Usually located in the engine compartment on the passenger side power distribution box. You will need to remove anything over the cover to open it. If the fuses are OK, tap on the relays or pull them out and push back in. If the fans are still not running, pull a relay and probe the socket terminals for power. Two or three of the terminals should have power, usually criss-cross from each other. Two are hot battery power, and the third is the "signal" voltage which triggers the relay to send 12V battery power to the fan. This signal voltage comes from the sensor at the thermostat. If only two terminal's have power, then I would replace the thermostat sensor if not both sensors.

Hope this is clear as mud! and helps! Please let me know what you find.

Is the engine running hot? The cooling fan won't come on unless the engine temperature rises to a point for the sensor to activate the cooling fan. Did this happen also back in warm weather, or has it just started now in the winter?

Chances are it simply hasn't warmed up enough to kick the fan in. It may well be running while you're driving, but you'd never be aware of it.

If you have done this already,then bleed the cooling system,this is all you lack,just get the air out of the system,two bleed ports,one on the thermostat housing,and one on the engine near the water pump,just bleed them out as the car warms up,the thermostat bleeder last,if this was at all helpful,please rate,thank you.

check if the fans work by putting a jumper wires to it, unplug the fans and get two thin wires attach one to a ground then to the other one to a power source touch the terminal be very careful the fans will come on if they work. If they do work then you have to unplug your temp sensor if the fans click on that's your problem. The car has to be warm up first then turn it off but leave the ignition on. If that doesn't work its your fan relay or a bad wire

cooling fan or heater fan? if its cooling fan then the coolant temp sensor is bad

check if the sensor is driving the correct polarity cause this is an electrical supply fault your fan is ok try to check the polarity using a multimeter device

Take it one step at a time. First, replace the coolant sensor and try to get the car to start WITH the sensor connected. Make sure that you DO NOT use any teflon tape when installing the switch (this will isolate the switch which will not ground it, making it not work). Th computer receives signals from numerous sensors, and makes adjustments according to inputs received. When the computer gets a signal that the car is still cold, it will adjust the fuel/air ratio to make it run richer (more fuel than air). Once the car is running it will run rough due to a improper mixture since the computer is never sensing the car is warmed up since the sensor is unplugged. This will also account for the slow start due to a richer fuel mixture.