Signal light problems

So I recently replaced my signal light switch on my dart, prior to the new switch both brake lights worked, but after installation Only one worked. The bulbs are brand new, all the lights and signals work, the lights just don't work when I press the brake pedal. I thought I messed up the signal light switch so I was checking everything, and when i was checking I must have shorted something because the done light went out and I blew out fuse number 3, and now both brake lights don't work but signals and lights work. I'll replace the fuse, but what could be causing the problem? I'm really clueless.