Hi folks, this is my first post, thanks for having me here. The rain sensor in my 2003 C320 wagon did nothing on Setting I, or in some cases it caused the wipers to operate continually. On Setting I, the rain sensor is supposed to automatically control the wipers. This was literally the ONLY problem with this vehicle, otherwise it was flawless. I started checking fuses, when I got to Fuse #9 in the trunk panel, the 25a fuse was good, but the dome light suddenly went out (I had the trunk door open). Fuse #9 controls the dome light, rain sensor, sunroof, some illumination, and a few other components. I put the good fuse back in, but the dome light never came back on. Suddenly, the sunroof will not open by pushing the control normally; you must push it about 10 times for the roof to fully open. Closing works normally. So, now the dome lights, sunroof, and rain sensor - all of which are on Fuse #9, are screwed up.
All other fuses are good. I pulled and re-seated all the relays. I tried to reset the system by triggering and resetting the alarm from inside the vehicle using both the key in the ignition and the keyfob unlock switch. This did not work; the problems persist. I also checked the wiring near the fuse panels and this all seems good. I have a basic scan tool that found no codes. I researched and found little information, although there is a post about a similar problem on SLK World: /threads/fuse-9-blows-instantly.528693/. I didn't put the full link as I'm not sure about link rules here.
My question is this; how should I continue troubleshooting? Or, does anyone have any direct experience with this? Thank you!