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Engine cooling fan not turning off!

92K views 22 replies 19 participants last post by  astraboy 
#1 ·
I went to my car the other day to find a flat battery. :mad: I called the AA who said the battery was fine and it's possible the radiator cooling fan isn't cutting out when the engine is switched off as this is a common fault. I've just tested it and the fan does run on until the battery is flat. Is this a common problem? Has anybody replaced one before or know where they are located? And how much did the part cost? Thanks for any help given.
 
#2 ·
I had some problem with my radiator last month. I replaced a blown fuse and had no problem till now. You might want to have a look at your fuses. Specifically 5Amp fuse (for cooling fan/steering wheel). It cost me only 80 cents.

Or

There maybe something wrong with your thermostat (I went to the dealer and that is what they think initially). I do not know how much it would cost though.
 
#4 ·
Mine is in the dealer today with an identical fault that appeared on the same trip that the power steering pump failed. Killed the battery flat in about 2 hours. I had to recharge the battery and then reconnect it yesterday only when I was ready to drive to the dealers. When I reconnected the battery the system was instantly live again and the electrics/fan was on! ( battery sparked as connected!) even though the key was not in the ignition and the car had been sitting without power/not used for a week. They say it is due to the pump failure sending an overheating message to the fan?? But this does not make sense to me! I am waiting to hear back as to whether Mini uk are going to pay for the pump, so I will have an 'official answer' about the fan too I expect.
 
#6 ·
It is possible that two differnet fans are being discussed here. There is a cooling fan for the radiator and another one for the power steering pump. It is true that if the computer in the steering pump goes bad, it can turn on the cooling fan. The radiator fan is not controlled the same, the ECU turns it on with inputs from the fan switch in the cooling system. Chasing this problem will take some testing.
 
#7 ·
I've had this problem and was disconnecting the plug rather than the battery or fuse,after 2 days and as i drove into the mechanic i heard lots of clicking as in a relay,and it went back working with no fix needed.So i'd have somewone check the fan relay switch to see if it's stuck
 
#8 ·
My 02 Cooper S is doing the same thing. Radiator fan keeps running until battery dead. I pulled the rad fan fuse, fan stops. Replace fuse, pull RAD fan RELAY, FAN KEEPS RUNNING??? WTF??? I called Classic Mini, Mentor, OH USA and he says I need a new rad fan motor. I said "WHAT? the fan is running fine, just TOO much!" He said, yea, I know, the fix is IN the motor, about $200 for the part. I may have to find a work around fix for this. How hard can it be to put a relay on the thermostat signal to hotwire the fan? I can't be the first to face this, am I??
 
#9 ·
The pre face lift minis have a relay and large green resistor in a small black box in the fan assembly.

The fan can work at 2 speeds and on the faster speed the power steering fan runs also.

Under normal conditions the fast speed will never happen as the low speed will cool the car enough.

Over time the power steering fan will rust up and the one day when your car needs the fast cooling fans it will turn on the rusty one and the fuse will pop, its just a 5amp running the control system, do NOT put a larger fuse in! We have rewired many burn looms now!

The front fan relay can be changed with tools but is a pain to get to, the resistor also rusts and breaks, but there is a transient suppressor attached which will keep the fan running.

The face lift cars dont have the relay in the fan assembly at all. You can tell which type you have......If you just have 1 large connector with 3 used pins then its a later type, if it has another smaller 2 pin connector next to it then its the early type, the smaller connector is the control wires for the fan speed relay.

The fast speed relay is mounted above the internal fuse box on a small bracket.
I hope that helps!

Dave
 
#10 ·
Thanks, Dave! If I try to retrofit to a newer design, do you know if Ijust need to change the Rad Fan, or is there more to it? It still sounds like a wire-around is a possibility, however I certainly don't want to burn the loom. After I read your description, I searched and found this:
.mini2.com/forum/faults-fixes/118392-mini-cooper-s-problem-engine-fan-stays.html
It sounds like one whack could fix this 'permanantly'? Does that make sense to you?

Thanks again for the help.
 
#11 ·
I have a cooper s r53 2002! Came home today and fan would not switch off, looked on here
For help, because mine is pre face lift , the relay is mounted next to the resistor behind the radiator,( large and green im told ) so with it plugged in and going i got a small hammer and large screwdriver and tapped on plastic ( squarish box). It is located just about directly below bleed screw on top hose, 3 gentle taps and fan swithched off (hooray). $35 from bmw i am told and in stock , cant believe that ? Ha ha , guess i will replace it very soon, im thinking possible relocation for easier access if any more probs at a later date, im glad that worked , hope it helps somebody else with similar issues ?
 
#13 ·
Our previous MCS used to occasionally run the fan hard after the ignition was turned off. The "fix" was to turn the engine back on then off again. It did it once in a while not every time.
If your car is running the fan for 30 seconds after a gentle drive in UK December then it sounds like something may be wrong.
 
#14 ·
i have had a problem with my radiator fan, it was too much for me to put the car in service mode as i have no garage, my fan would not kick in at first stage and second stage, but the fan would kick in if i put the ac on, after going to a local mini specialist in dudley i played stupid and got a quote for a replacement fan for 170 fitted, so i went back home, and just by passed the thermal resistor and took the green and black wire directly from the fan put a relay on it and used thick wires and took a live from the fuse inside the car, which comes on with ignition as all the fuses on the engine side where live with the ignition off, so now i have the fan at second stage on when the car is on also the power steering fan which comes on with the circuit i put in, will put a on and off switch in side the car when i get a chance, its doing the job and my car isnt over heating now, i will either put a toggle switch on it or will put in a thermal heating switch on so it kicks in when it gets hot,, it a fiddly job you just need long nose pliers to get to the wires and i have un plugged the original plug, its better than paying for a fan that will do the same thing after a while,
 
#23 ·
Hey, I had this problem on my 12 plate mini clubman and Google directed me here. Poked around unde the bonnet, whipped the fuse cover off and gave the green relay closest to the windscreen a tap. The fan immediately stopped. Ordered a replacement relay from BMW and fitted it in seconds. Thanks for the steer everybody, needed my car over the next few days.
 
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