Hello, I have a 2001 Subaru Legacy Wagon and the flashers won't turn off - the rocker switch no longer works .?

Hello, I have a 2001 Subaru Legacy Wagon and I am having problems with the emergency flashers. When I purchased the car, the switch on the top of the steering column wouldn't work - which was largely ok because the flashers were not activated. Recently a friend drove the car and hit the switch on top of the column - it worked for him unfortunately - now they won't turn off. I tried unplugging the battery in the hopes that it would reset or something - that didn't work. I also tried digging into the steering column, but had no success there. Any suggestions are very much appreciated. I also noticed while looking for a reset switch under the dash that a green plug was disconnected, when I plugged it in the check engine light came on - I promptly unplugged it . . . Any ideas as to that?