I just did this to my E430.
The tool is easy to make to pull out the control unit.
Also, I found that the bulb didn't need replaced - it was the bulb connector that was not making good contact to the circuit board.
So, I adjusted the connector (i.e. bent it back to original) and twisted it back in.
Nothing to it!

Good luck - if you need a drawing of the tool I can send it to you - I fab two myself in about 10 min.