Where do I connect the ground wire in the fuse box?
 

First off. I have zero experience with aftermarket electronic accessories. I just bought a Garmin Nuvi GPS and I did not like the idea of using the cigarette lighter so I decided to hardwire it to my BMW X3 2004.

I found a fuse to connect it to but where do I connect the ground wire? I was told to look for a black bolt or screw. I do not see it anywhere. Anyone know where it is located? What does it exactly look like?

Any bolt/screw that is connected to the the frame will do for a ground - if your ground wire isn't long enough just use more 10 gauge ground wire.

You probably don't want to hear this, but I found the best solution on my wife's 07 X3 was to drill a small hole in the inside bodywork behind the passenger's side kick panel. I then used a self tapping screw and star washer to get a good ground. Just be very careful that there is nothing behind where you drill and, obviously, that you don't drill through to the outside body panel.

If the ground wire isn't long enough, extending it with the same size wire will work fine (probably number 16 or 18 for the Garmin).

Lou

There is a large connector block above the fuse box where common signal wires are joined (reverse signals, ibus and ground). The brown wires are ground.

To get to it, remove the entire glove compartment (8 screws), release the fuse box from one of the hinges (unhook) and drop the fuse box as low as possible. The connecor block can be unclipped or you can remove the ground bank of connectors.

There is a screw on either end of the fuse block, at the top, that mounts the block to the bare steel framing. The peice of metal the block is mouted on is a great ground. Just back the screw off and connect your bare ground wire on the top side where the screw clip is (more metal there) A ring-terminal crimped on the end of the ground wire, would be even better. You could drive a self-tapping screw into the metal fuse block mount but using the existing one is easier.