BMW X1: Whistling noise from door mirror area between 40-50 mph (60-80 kph)

Problem:

• We have a 2011 BMW X1 in for service and the customer has complained of a whistling noise from the door mirror area when driving at a constant speed between 40-50 mph (60-80 kph). 
• We have heard the noise on road test but we are having difficulty finding the source of the whistling noise in the workshop. Have any other X1 owners reported a whistling noise before?

Solutions:

• Yes, this whistling noise has been reported before on several BMW models produced up to 23/11/13. 
• The noise is due to excessive clearance between the door mirror housing and the door mirror upper cover. Remove the door mirror upper cover. 
• Cut a length of felt tape, available from BMW parts department, to a width of 9 mm. Apply felt tape to the indicator repeater lamp Fig.1.1. 
• Refit the door mirror upper cover. Carry out road test to ensure whistling noise has been eliminated. 

NON-START AND ALTERNATOR WARNING LAMP ILLUMINATED

Problem:

We are having problems diagnosing an electrical fault on a 2010 Volkswagen Polo 1,2. The vehicle cranks but won't start and the alternator warning lamp is illuminated. Our scanner has read several faults codes that relate to low battery voltage. We have charged the main vehicle battery and the vehicle will still not start. Can you help?

Solutions:

• The symptoms you describe are common on all Polo (6R1) models and the cause is a poor connection between the engine earth lead and chassis earth point due to corrosion. 
• Check for corrosion between the engine earth lead and chassis earth point. Replace component(s) as necessary. 
• Fit a new earth lead stud on the engine mounting and tighten the stud to the correct torque setting. Check the vehicle starts and erase all fault codes.