Dash removal

I removed dash to change heater coil. I hit a wire. There
was a spark. Funny noise, clicking. Disconnected
battery. Fixed wire. Replaced heater core and reinstalled
dash. Got an extra plug that I don't know where it goes.
It's a 20 pin computer-lookimg connector. Small. Thin.
GF thinks it may be from old alarm system. I and three
other people (one of whom works on cars for a living)
can't find where it goes. Now the brake lights don't
work. At first I thought it was plug, but now I'm thinking
maybe that plug was never plugged in and I just fried
something. Under the hood I heard a funny buzzing
noise coming from fuse box I think..illumination on
gear doesn't work (to show what gear you're in).but
other lights do. No brake lights. Can't shift out of park
unless I hold a small tab down on the stealing column.
Then it shifts and drives and brakes fine, but no brake
lights. Everything else seems to be working fine.i
checked abs fuses, seem fine. Switched all the relays
with eachother, didn't see any change.
Any ideas? Any help is much appreciated