I have just noticed the cooling fan on our MCS 2005 R53 turns itself on for 5 to 10 seconds then goes off, then 15 to 20 seconds later comes back on again even though the temperature gauge is reading normal (halfway) and then does it again & again.
Check both low and high speed work, by turning AC on and waiting for low speed to come on within a minute even on a cold engine. Sounds like only high speed works in your case, which would be because of a broken resistor, which is part of the fan assembly, common fault.
