I've got a '98 M3 that has a/c issues. The blower works and air comes through the vents as long as the A/C is not on. As soon as you push the a/c button, the air coming through the vents shuts off. The compressor kicks on, so I know that part is working. A good friend told me that it's most likely one of the flap motors, but I want to make sure that I order the right one, since there are so many. Does anyone know the part number for the correct motor? Thx!!