I'm trying to replace my rain sensor on my clk but havent been able to find any threads to guide me. Has anyone done this before and if so any instructions would be greatly appreciated.

 

Are you trying to replace the actual sensor or the lens? The sensor just snaps onto the lens, but the lens has to be adhered to the windshield using a special glue. Any bubbles, even very tiny, hardly visible bubbles, will cause problems. MBZ recommend replacing the entire windshield with the lens being factory attached.

 

No I am just replacing the module not the actual sensor.

 

Just remove the plastic cover behind the rearview mirror. It's held onto the lens with a sliding plastic clip.