heater fan noise when speed of fan is increased
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2004 BMW X3 Question: heater fan
Answer #1patrick mannion from Greg Solow's Engine Room, March 01, 2009, 23:10Master
Does it sound like something has got caught in the fan or the fan bearings are failing? We frequent see mice building nests causing debris to get jammed in the blower fan and ducting. Removal of the heater fan, inspect for debris and testing it across a battery on a work bench is probably the diagnostic path to follow.