Originally Posted by pmanliu

Your resistor for your low speed fan is probably shot, thus why your high speed fan is turning on after the car is off in order to cool it down.

Reference the later pages in this thread for the fix. Its relatively simple and <$10. https://www.northamericanmotoring.co...-solution.html

Originally Posted by r53coop

Could be stuck relay as well.

Originally Posted by cooperSml

1) Turn off the car if your fan is still running disconnect the battery.
2) Open the fan connector (on my case Cooper 2006 S) it is only one connector for fan 1st stage and second.
3) Reconnect the battery, the fan should not be running
4) Now with a voltimeter measure on the fan connector (side that connects to fuse box)
if on either 1st and 2nd stage pins you have 12 volts
5) If so the relays must be operated. To confirm remove the relay fan 1st and 2nd stage.
6) Now on the fan connector you should NOT have voltage.
7) If there is voltage you must have a short in the cable.
Note: The Control Module activates the FAN based on temperature readinds of the car.
If CM is operating the FAN even with the car not running it is possible because there is
situation where the car is leaking coolant when you stop the cast iron block is still heating
up and the CM keeps the FAN running until the temperature drops.
In your case (if no short circuit somewhere) my guess is that in some how the CM is thinking the temperature
is above the threshold and keeps the FAN running regardless.
======================================
Regarding the weird behavior with low voltage.
A health battery when you start the car goes to a 9-10V due the load imposed by the start motor.
If a battery is not healthy and has a weak charge it can fluctuate more, on this case causing oscilation
in voltage and the effect can put electronics in the threshold almost cutting off where you can observe weird
behavior.
I had a drain of current (almost a short circuit ) in the clutch of my AC a while back, everytime I was
turn the AC on lights on the dashboard were coming with no reason.
========================================
Do you know how to use the On Board diagnosis on your Mini?
You could use that to see how the CM is seeing the coolant temperature in your MINI.
When you enter the test MODE you can check stuff like this, but you are going to be insterested on
TEST 9.0 and TEST 7.0
1.0 Chassis number
1.1 Kilometer count
1.2 Parts number
1.3 Coding-, Diagnostic- and Bus-index
1.4 Production Date (Calender week/year)
1.5 Hard- and Software status
1.6 Injectorstatus, Cylinder count, Engine factor.
2.0 Combisystem Test
3.0 Service intervall counter
4.0 Actual fuel consumption in l/100km. eg.0154 = 15,4 liters/100kms.
4.1 Consumption in liters/100kms.
5.0 Distance consumption in l/100kms.
5.1 Actual rest distance with available fuel in Kms.
6.0 Actual amount of fuel in tank. eg. 123321 =12,3liters left 32,1 liters right
6.1 Total amount of fuel in tank.
6.2 Show value of Fuel guage. 1= both senders OK, 2= sender failure, 3=ti signal unplausible (no reading)
7.0 Actual coolant temp.
7.1 Actual outside temp.
7.2 Actual engine revs.
7.3 Actual speed
8.0 Hexadecimal readings of menu 7.0 to 7.3
9.0 Actual on board voltage (Battery)
10.0 Land codes
11.0 Unit codes
12.0 No funktion
13.0 Gong test
14.0 - 14.4 On board diagnostic codes. eg 000000 = no failures
15.0 - 18.0 No funktion
19.0 On/Off for Test menu.
20.0 Correction factor for Fuel consumption
Formula for correction:
Shown consumption x 1000 / user defined consumption
Push the trip reset button to begin the correction. Numbers count up from 0-9, when correct number shows push trip reset button.
20.1 Sets 10ths. for consumption factor
20.2 Sets 100ths. and 1000ths. for consumption factor
20.3 Saves the new consumption factor and shows new value
21.0 Software reset. (Same as disconnecting battery)

Originally Posted by Mini-Moi

This is completely normal behaviour if the engine temp is high when you turn off the car. Does nobody read their manual?

Could be not cooling properly or it could've been a hot day.