Mercedes-Benz Forum banner

Fuse #9 Circuit Components @#$%ed after checking fuse in 2003 C320 Wagon

405 Views 4 Replies 2 Participants Last post by  RussHudson
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!
1 - 3 of 5 Posts
Thanks, rudeney. Actually, the sunroof started working again on its own while on a drive a couple days ago to Indiana and back from Maine. Once it started working again, it has continued working without problem. On this same trip, the rain sensor also started working for one glorious hours during days of rain. But then when I stopped for gas, it did not resume working. The dome light also worked once during the trip, but then not again. And no, it doesn't work manually. I also noticed that the driver's side visor light flickers on and off, depending on how you bend the visor. So, I now know that all of these components work. Intermittent short somewhere in fuse circuit #9? Could the visor be to blame?
Okay that makes sense, when adjusting the visor I was probably partly pulling it out of those contacts. I'll pull that overhead control panel and see if I can find anything, if not I'll look at a replacement. Thanks again!
1 - 3 of 5 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.