your hose may be broken, the washer fluid pump might not be working, or the sprayer nozzles are plugged up, and need to be blown out with your air compressor.
Your headlight wipers should come on when you spray your windshield washer fluid.
1) blown fuse (2) faulty wiper switch (3) no fluid in the reservoir (4) spray pump is clogged OR has has failed (5) spray nozzles are clogged with crud. Good luck.
if one spray doesnt work when cold, i would check that the fluid is not the cheap one that freezes easily
check the fuse box, maybe there's a problem with the connection between the switch and spray. bring it to a mechanic if you don't want to get your hands dirty :)
Because you haven't gotten them sufficiently excited? Also consider: Tank empty. Fluid diluted with water and frozen. Disconnected or leaking hose. Bad pump. Electrical problem.
you can get something called spray and wipe then get your windscreen wipers and clean it
The wiper control arm on the right of the steering column pulls forward to control the rear wiper. Push in the end button to spray wiper fluid. Push up to turn wipers on with arm pulled toward you. Push arm back away from you to return to front windshield wipers. Took me forever to figure this out as this was a work vehicle.
The can contains a fluid, and a propelling gas. When you push down on the valve, it opens. The pressurized gas inside pushes the fluid out through the valve and the spray nozzle.
From the way that question sounds, there is nothing wrong. When you spray washer fluid on the windshield, the wipers are supposed to automatically come on for probably 3 or 4 swipes, then turn back off - it's a convienience thing when you need to clean your windshield. If your wipers are coming on automatically at random times, then you probably have a loose connection at the switch.
Blast the fluid lines with air, if that doesn't work than you either need a new spray switch on your steering column or a new pump, either of which I'm willing to bet are not cheap on a Mercedes
most times starter fluid is sprayed through the air filter,if this is hard to get at you can disconnect one large air hose on engine side of air box and spray in there .remember to reattach hose after starting before driving off
Starter fluid should be sprayed into the throttle body intake. Spray in small amounts, as the fluid is highly flammable. Any over spray could ignite if the engine backfires.