The 2007 Mercedes-Benz c280 is not listed in the aftermarket references which usually indicates that they are special M-B wiper blades and wiper arm attachments. Since you have to go to the dealer anyway for wiper blades, ask them for the instructions too.
This is pretty simple. Just turn on the wipers and stop them while the arm is in the middle of the windshield or there about. Then just change as any other wiper.
diagram for the fuse box in the trunk of a 1995 c280
first thing i would check would be all the fuses. then the light switch
If this is the single blade wiper it's the motor, its gears or related. You probably will need a new one. Rebuilts w/ install you're talking min. $500, maybe $700 depending where you are.
At the bottom of the wiper is a box about 6" long and about 5" wide. This is very hard to open, maybe invest in special tool. It is likely that a cog wheel has come off an not a scredew up wiper motor. It is also quite likely that a cog has worn itself out, in which case you need to replace the cog. The wiper motor is extremely expensive... even used, so I hope there is some noise coming from this box when you try to use your wiper or your wiper is likely banjaxed...
This vehicle has special Mercedes-Benz attachments and takes special Mercedes-Benz wiper blades. Since you have to go to the dealer to get the wiper blades, you can also ask them for the procedure. This vehicle is not listed in aftermarket catalogs - that is why I can't answer it fully.
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