Today the cooling fan in my 2002 X5 (mileage: 92K) turned on by itself and will not shut off. Even with the ignition key out and doors locked. There are no indicators coming on the and A/C lights are not on. The only recent service I had to it was front brakes about a week ago. What could be causing this? Is it dangerous to drive like this until I can make it to the dealer? Thanks in advance for any advice.