How to disable airbag in C230K 2005
 

I'm going to help a friend with a 2005 C230K power window (driver's door) problem.
I went to the library and got the correct Chilton manual. It has a warning about
being sure to disarm the airbags, and 4 steps are provided:

1. point the wheels straight and remove the ignition key
2. disconnect the negative battery cable,
3. wait 2 minutes,
4. If you're working in the passenger compartment, disconnect the electrical
connector from the control unit on the transmission tunnel.

There's no picture provided. How do I find the correct electrical connector
to disconnect? Or is there some other way to temporarily disable the airbag
in the door while we try to figure out what the problem with the power window is?

Walt