My '96 SL320 developed a rather strange electrical problem today and I'm not quite sure where to start. It was a rare dark, rainy/snowy day here in Albuquerque and I had the parking and fog lights on and occassionally the wipers and windshield washer. At one point I noticed the washer fluid warning light come on but didn't pay much attention to it. When I stopped and turned off the CD player I could hear a nasty clicking/humming sound from the engine compartment that stopped when the light switch was turned off/started when I turned it back on. The fluid reservoir was dry. After refilling the reservoir I discovered that the headlight washer pump runs constantly as long as the light switch is in any "on" position. The headlamp wipers do not run (unless the main wiper are on). I pulled fuse #1 which has temporarily cured the problem. Any suggestions??