Hello, all.

I was hoping I could some help from you masters...

The combination switch doesn't switch on the water for the windshield. she's a 2003 c200cdi estate elegance level. I have removed the pumps (2) plugs on the water tank, switched them, and made the rear window command actuate the windshield pump. Now, I know the rear system is a relay-based one. But the windshield is an electronic, non-relay based. The electronics of it come from the multiple function control module nr. 1. So, what would be most likely to have gone? The combination switch or the electronic module? Is anyway we can check it or reprogram it via the engineering mode at the command 2.0 panel?

TIA

I'd expect the switch itself to be the first failure suspect. Test by jumping it.

you cannot test it by jumping it since it's not a hardwired switch. It's CAN controlled and sends it's signals to the front SAM unit via CAN. If you are not getting any power at the pump, then check fuse first. Then you will need to test switch and or front sam unit with a star diagnose system.

I agree with Sunil's analysis, but I am not sure there is a fuse to be checked. Many circuits controlled by the front SAM measure the current flowing in the circuit, and switch off the power if excessive current is detected. A fuse to protect the wiring would be redundant in this case. Mercedes fuse charts report "electronic" for the windscreen washer pump.

Yes. There is indeed a fuse F46 on the engine bay, for all of the controller. If this fuse had gone, none of the functions would be available, but the only thing missing is the washer. I believe the controller can malfunction by loosing one or more of its functions, but I guess I'll have to dismantle the trim/steeringwheel/other to check the switch...