How to test the radiator fan on a Mini R50 2002-2003
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- Опубликовано: 10 ноя 2016
- On later models that don't have the smaller connector (relay in the fuse box rather than in the radiator housing), you should be able to test both fan speeds using the larger connector.
There is a 0.3 ohm 100W resistor attached to the radiator that provides the slow speed, this often fails. If you find this is the case, one option I read was to connect a new resistor to the low speed wire from the ecu, with the other side connected to the high speed wire. This just bypasses the radiator's internal resistor and you don't have to take the radiator apart.
Next I tested all relays and fuse under the bonnet and in the passenger foot-well. The F5 5A fuse in both had blown, so I replaced them. Tried to turn the power steering fan and noticed it had seized (the power steering fan and radiator fan use the same fuse).
I removed the power steering fan, cleaned it up and it tested ok so re-installed it. Now it's all running sweet again. The coolant rarely goes over 90 degrees.
If you're having overheating issues like me there are a number of possible faults. My recommendation is to check your radiator cap is making a good seal and is not damaged or distorted. Also replace your thermostat. Both are cheap and reasonably easy to replace.
My 2002 is unfortunately not OBD2 compliant however the in-built test mode is just as good for monitoring coolant temps! With the key turned off, hold the odometer button and turn the key to the first click. Press the odometer button about 4 times until it says 19. Press it again when it says L_OFF then press until it says 7. You can start the car and it will report the coolant temp until it's turned off. For reference, my car seems to stay between 86-90 degrees. 
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Thanks!! I was wondering if my radiator fan was working. I did a quick test & my works!!
this video is a lifesaver. Thanks Ian!
I get nothing from the battery directly low or high . Is there a way to test the motor without stripping the car down ?
I think I might be think8ng the low speed fan is the high speed fan judging by the noise. Would it be on constantly with aircon or just pulse on and off do you know??
Mine is the resister is there an easy way to do the job with outtake ing the front bumper off and the unsaid to get to the resister fan. I was thinking of cutting around the resister Plastic save me a lot of the time towards, fitting a new you resister. cat around the plastic was the resister goes with a Stanley knife and a little gas blow torch job down 1 hour. the 3 wires were disconnected ted from the resister.
Have a look at the video description text. I wrote a section on how to easily fix your resister fault.
I did see it but now you pointing out to me again I understand how to do it. Thank you.
Thx great video, in my case the high speed fan is working on the lower pin in the large connector (regardless of the smaller connecter being connected) but lower speed is not working. Would that mean the resistor in the radiator housing is faulty?
Thanks Ian - similar problem with my 2002 where the fan just stays on after the car is turned off (have to disconnect the fuse to resolve it) but will then sort itself out a few trips later. I’m convinced the relay is getting stuck every now and again and if that’s the case do I need to replace the fan motor to fix it?
This might help. www.justanswer.com/bmw/2leev-2002-mini-cooper-cooling-fan-continuing.html
when I give 12v to the low speed circuit, nothing happens, when the relay is given 12 v the high speed fan works , but when everything is connected, the low speed and high speed fan never come on and the car boils over.
Using this method, any idea why the low speed fan would work but the high speed wouldn't? When I provided power for the high speed, the fan would click once, and then click again once I removed power.
Check your fuses. I think it might be the 50A one. Check that there's 12V coming from the fuse box to the brown and red-blue (thick) wires. If there is power, then your relay is probably no longer working.
There's a good circuit diagram here -
drive.google.com/open?id=0B6SS0MH5ttMWSzNPMXF2Z3prZVU
The 50A fuse (FL11) is still good and I confirmed power from the fuse box to the high speed wire (thick red-blue). I **thought I** positively tested the high speed fan relay (R4) for continuity but it turns out that relay is NOT for the high speed fan for my 02 (or early 03s)... (that wiring diagram then is for 03/04+) so my car doesn't have a high speed/stage II fan fuse box relay (...?) so it must be built into the fan itself...? I can't find an 02 wiring diagram to confirm :/ That does make sense why I heard the clicking from the fan - that should be the relay clicking then with power, but I guess the contacts could still be bad? I suppose I'd need to get access to the fan itself to check...
Provided my assumptions are right, I think this is it actually, what would need to be replaced within the fan housing itself: www.detroittuned.com/dorman-fan-relay-kit-gen-1/
Chris D'Antonio did it end up being the relay inside the fan itself ? I think I’m having the same issue
Very helpful Ian, I'm in the same boat, your tests prove the resistor is fine. Do you know what controls the 1st stage fan, where it gets a signal?
The computer (ECU) would send a signal through the relays and fuses. My power steering fan was clogged which blew the same fuse that the radiator fan uses. So check there first. It's not hard to completely remove the power steering fan, clean it up and test it by connecting it straight to the battery.
Otherwise overheating could be caused by the thermostat, temperature sensor, airlock, radiator cap or worn coolant pump. It's an old car :(
My mini coopers fan stays on after I turn it off and will turn off after a couple of mins. Anyways I can fix this without needing to replace anything? Bypassing and all that???
If it's just running for a couple minutes, that's probably normal behaviour. I wouldn't worry about it unless you notice it staying on for longer periods, which could indicate a stuck relay
Hi, it seems my high speed fan is starting almost immediently the car is turned on and doesn't stop. I have no engine lights on, new coolent and engine is not running hot could you please suggest what the problem may be
Sorry it's taken a while to get back to you. It sounds like your relay is either stuck on, or your ECU is constantly telling it to turn on. Check if there's power coming from the ECU. If there is it's a bad ECU, if not, then a stuck relay.
Koo vid
Did you ever figure out the problem? Also thanks very helpful.
I think the above helped greatly but it was an old car and soon started overheating again. I'm guessing air in the system and possibly even a worn coolant pump.
It had a number of other faults and I'd spent my budget so I ended up trading on a new small car.
@@ianmurnane744 Lol