Electrical issues

My cars electrical system is going haywire. My windshield wipers will not turn off even though the switch is in the off position. The horn will go off for about two minutes at a time. The doors lock and unlock intermittently. The "brights" light on the dash is illuminated even thought the actual lights are off. The only thing that I can think of is: There was a heavy down pour yesterday and my door leaks and enough water got in to make my seat damp. Probably a short somewhere. How do I determine where the short is and how would I fix it? Thanks in advance.