I've got some additional lights I'm trying to install, and I need a 12v power source. Where can I tap into? Thank you!

 

Either get an "add-a-circuit" adaptor (plugs into the fuse box in place of a fuse, gives fused power to another circuit) or tie into that 12v+ battery post to the left of the airbox under the hood (on an "s" model - the place the manual tells you to attach a jumper cable). On a Cooper, you can tie into the 12v+ battery cable.

Either way, be sure to fuse the power wire. The adaptor has a fuse built in. Also protect the power wire by making sure it doesn't come adrift under the hood, doesn't rub against anything, and is concealed within a wiring loom or protective cover to prevent abrasion over time.

You can see the attach-a-circuit in my fuse box at the bottom of this picture

 

I kept this link as a reference for the Littlefuse Add-A-Circuit Fuseholder:
http://www.partsexpress.com/pe/pshow...83&PID=1828117

Of course, Littlefuse produce should be available at your local auto parts store (more than likely something they will have to order).

 

My local Advanced Auto Parts has them in stock.

 

That's pretty much what I have...

 

I have instructions on my web site for a normal low-power (electronics) tap:
http://www.jwardell.com/mini/fusetap.html

Be aware the add-a-circuit is only to be used up to 15A. If you mean you are adding additional headlights or a stereo amp or something powerful, then a direct tap of the battery or front power post plus a dedicated inline fuse is the best choice.