I recently purchased an 2009 C63 and when I try to use the windshield wiper fluid, only the headlight sprayers activate. To activate it, I am pushing and holding inwards on the stalk towards the wheel. I'm not sure if the pump is the problem, the line to the windshield or Im just missing something. Any advice is appreciated!

 

There are two pumps, one for the headlights and one for windshield. Getting to the pump and tanks is pretty easy, just take out the left front wheel liner.

Test for voltage at the windshield pump to determine if pump is bad. M5 is the windshield pump.

The headlight pump only comes on every X cycles of the switch.