Hey guys,

It never rains, but it pours! I've got an E34 M5 that will go for ages without any problems, then I'll get hit with several problems all in a row. This week, it's heater problems.

Normally, I use the climate control set with the air conditioning on all of the time, with the direction controls set to "Auto", and the temp set to the desired setting. If the climate control (CC) needs to heat up, I never get air coming out of the face vents in the dash, but if the CC needs to cool down, then I get cold air from those vents.

That's OK, it keeps the car nice and comfortable.

Over the weekend though, weird things started happening, and it ended up that I wasn't getting any heat from any vents at all, no matter what I did to the control. I suspected that I just had an air lock in the heater (the cooling system was drained a little on Friday when the cam gears were fitted), so I bled it, and that seemed to work sort of OK for a little, but then yesterday, the heater died again. I took it to my mechanic, and he tried bleeding it for ages, and then found that the small pump that pumps water through the heater had failed and was leaking. So, I left the car there overnight, and he replaced the pump for me today. When I picked the car up tonight, he said it was blowing very hot air, so I took the car and off I went. I set the CC to how I described above, and I got lots of very cold air coming out of the
face vents. Even if I turn off the air con, I still get cold air coming from the face vents. So, for now, I'm running without the aircon on, and with all of the face level vents closed. At least the car gets warm now.

I was talking to the aircon guy who just happened to be at my mechanics, and he was saying that there are 4 stepper motors in the dash to control the air flow to the vents, and he suggested that the one that controls the air to the face vents has probably failed. He also said that they are a nightmare to get to, and they are pretty pricey.

The other thing that it could be is that the knob in the centre of the face vents that controls the temp of the air to those vents seems a little different to me, maybe it's come loose? How do I remove that vent to find out?

Does anyone have any other suggestions of things that I can check before I outlay heaps of cash?

Thanks for any advice

Regards

John