If your blower motor has failed it may have been caused by a clogged cabin filter. When was that changed? The blower motor is within the firewall/cabin at the center. It can be a very expensive repair if done at a qualified tech/shop.
I'm not sure if the 2004 retained the original BMW climate control system. If so, the blower motor is very time consuming to replace, you need to remove seats, center console, entire dash and fan unit. Before going to these lengths check the fuse and the control module. If not these, the most likely cause is failure of the resistance pack which controls the speed of the fan. This is pretty common on these systems. Sadly this is located within the fan housing too. Replacement of fan or resistance by a Bentley dealer will cost more than the car is worth. Cheaper to sell it and buy another with a working fan. If you are a competent mechanic you can do it yourself (I have done it) but lots of hours and you need to drain the AC and heating systems. You also need the shop instructions.