Removing the broken bolt can be simple or a real pain in the a$$.
First off, you need to get as much room as possible so you can get at the broken bolt straight (remove upholstery or engine if needed).
Soak with PB Blaster penetrant
You can buy a set of reverse rotation drill bits to drill into the broken piece (if not frozen, some will come out with just the drill bit) or drill with a standard drill bit and use an Easy-Out removal tool.
Just don't get in a hurry and do more damage.
And if the threads are damaged you can get a Heli-Coil kit to install a new thread insert.
Good Luck
