I have a 2008 mini cooper base 2 door hatchback. decided to install an after marked stereo. hooked up the wires to test before bolting all of the stuff back in and it all worked great and sounded great. decided to go ahead and run some wire for a future sub. removed the battery to access the hole in the firewall and ran the wires (but did not hook them up. re installed the battery and now the only thing that works are the parking lights and dome lights. put the key in and nothing. no start no radio no windows or locks or ac/heat controls. as i said the only thing i unhooked was the battery and did not hook anything extra. checked all fuses cannot find a bad one.

 

Have you fixed this yet? If not, check the terminal connection on your battery. It's very easy to incorrectly tighten....that is, when you tighten the nut it can tighten but the connection to the terminal is still loose.