Queen Sadim

Yesterday, when I shut of the ignition, the stereo cranked out loud radio static. I was unable to reduce the volume or turn off the stereo, even when the car was running. My boyfriend tried pulling the fuse, to no avail. He then disconnected the battery, when he reconnected it, the problem was solved, however, the right signal is now stuck on. When I switch the arm to off position or to signal left, nothing changes, right signal remains on. I tried driving the car and turning the wheel to disengage the signal. No luck. Then my bf tried pulling that fuse, which also did nothing. Any suggestions as what to try next pls?