Jeremy-
I highly recommend that you inspect the wiring, especially in the engine bay. The 92-95 SLs (especially the sl500) suffer from improperly manufactured wiring throughout the entire car. The plastic coating on the wires breaks down over time and just falls off. The resulting issues can range from unusual electrical issues to electrical fire.
The wiring MAY have been replaced under warranty. If not, it is a $7000-$10,000 repair. If the wiring looks to have the symptoms, DO NOT TOUCH IT! It will only make it worse.