Need advice on S420 AC

[emcinnis]

I am having problems with the blower motor on my S420, stays at low position even when it is at high speed. The air is very cold, but seems restricted. I have read a lot of posts on different boards. I was getting ready to order a blower regulator when I stumbled upon a reply about cabin filters. Now I want to check that first, as I have in my younger days spent a lot of money thinking I was smarter than the mechanics, bought parts only to find out it wasn't the problem. Ended up taking it to a mechanic to fix in the end. Had the parts left over for later. Now how do I find the cabin filters as it seems impossible to find a good mercedes repair manual for late models.