2007 Escalade Electrical problem

I recently tried to jump start my 07 escalade, now I have lost all my electrical power except for my interior lights, they come on very dim. I have fully charged the battery and have checked all fuses. I did find a blown fuse under the hood labeled ECM/Throt. I replaced the fuse still nothing. When I rehookup the battery I hear something running underneith the truck below the drivers seat, it sounds like the fuel pump but it doesn't turn off until I disconnect the battery. Could this be a bad battery? I used a multimeter and it shows 12.7 volts.