I am starting to have regular "warning lights" come on when no problem is found. For example, brake light and coolant will intermittently come on when I'm driving. Several times the "windshield washer fluid low" light says "fluid low". Each time I'd check the WW fluid -- it was full -- the coolant was full. The brakes have been checked numerous times. My thought is: sensors are not working or computer is not working. My 1990 325i convertible is in impeccable condition, inside and out. It has 82,000 original miles. Any ideas on where to start troubleshotting this?