How do you check the Blower motor circuit before replace it?
Symptoms on 94, 540i: Fan is running but there is a humming noise at all speeds(1 to 4). When blower switch set at speeds 1 to 3, then arbitrarily shut off itself every minute or two. But when it set at speed #4, it will continue running with it generate a very lound noise.
Does anyone has this problem before?