Fan help

Hello all I have a 1993 M5 with a little over 40,000 original miles on it as you can see I dont drive it much. My problem is the electic fan, I dont think its coming on causing the car to run hot at a light or when its parked and running. How hard is it to replace the fan and or to check it. The last time i drove it was 2010 now on the dash it says coolant. Can any one tell me what that means.