I have a 1999 SLK230. A couple of days ago, on a very hot day, the turn signals on both sides AND the emergency flasher quit working, with the lights staying on rather than flashing. I tried to repeatedly operate all of the switches, but nothing helped.

I rechecked the car in the morning after everything cooled down, and the problem disappeared.

This has been an intermittently recurring problem over the past 4 or 5 years, but since the problem always seems to correct itself before I can have a shop look at it, nothing could be done.

Is there a component I can check and/or replace to repair this issue. Where can I find a wiring diagram, and a drawing showing where these components are and how to access them?