Originally Posted by RL in Florida
I've done the vampire-clip attachment on my other cars, but my dealer made it clear that if anything went wrong the the electronics, that the warranty would not cover any repairs. I asked them to install it, but they wanted $375, and said that it would still invalidate any warranty claims on electronics. So i used the add-a-fuse technique that everyone has described (got it at Advance Auto Parts).
I just wanted to contribute this little hint: Go find a trim tool set on the internet. I bought one for my NSX and Gallardo so I could remove interior garnishes and such. The first photo shows the tools.
You can use the tools to gently pry up the headliner, a-pillar, weatherstrip, and the power cable (aka telephone cable) slips right in. You don't need to unscrew or remove or alter anything.
Behind the glove compartment, there is a small gap on the left side bottom just in front of the fuse box. Just push the cable up from the bottom, and feel for it with your other hand.
The rest of the install (i.e. finding a ground, which fuse to use, crimping vs. soldering) has been described by other members, so I'll skip that part here.
Hope that helps!
I would mention not to fully remove the "A" arm cover, just remove the airbag plastic clip and loosen screw which will give you some room. I made the mistake thinking it was just like the 335i cover. There are 2 alignment clips near the windshield that are a bitch to line back up. Then one of of the "A" arm cover clip fell off and fell into that little crevice. This caused alot of delays.