Re: headlight housing assembly
The spring clip, so long as you didn't lose it (God forbid), just slips 2 prongs into little raised slots in the metal face of the H7 bulb mounting surface.
use a pair of locking pliers (hemostats or surgical clamps) and just do 1 prong at a time.
And tie a thread to the clip before you staryou REALLY don't want to lose a clip.