oh and apparently you cannot check for 12V because it is a stepper motor of sorts.

I got the front bumper off , but now I'm stuck ! Doe's any one know where I can find a link with instructions that will help me replace the fan?

you are right
 

how do you do?

Here is the link I used:

http://www.xoutpost.com/bmw-sav-foru...ditioning.html

The DIY is from a 3.0 version, and it worked on my 4.4.

Good Luck

Here's a complete DIY for the aux fan:

You do know that was posted 4 years ago. Hopefully, the poster figured how to replace the fan by now.

Yep 100%. But people use the search function and arrive at these threads. So I will continue to contribute.

As to the OP question about how to test a fan, if you have a signal generator, 12 volt battery you can MacGuyver this set up and test your fan. Lot easier to just get it scan.

https://www.youtube.com/watch?v=-iAPRl984iA

Hmmmm.. Replaced aux fan on my 2005 3.0 three years ago. Now I get hot air while waiting at stop signs. I will need to be sure this time that it is really the fan that has gone bad.
Can I use a battery charger (from Costco) which is also a jump starter to test the fan?

Nope. You need a much more complicated test setup as shown by upallnight a couple of posts back or use a BMW scanner to read the DME codes.