W211 Windshield Washer Troubles
 

The windshield washer on my 2006 E320CDI is not working: I push and hold the button and get only one complete sweep of the wiper - no pump sound, no squirting, only one sweep of the wiper no matter how long I hold the button.

The problem originally showed up with a "washer fluid low" light on the dash, so I figured I was just out of fluid, but refilling the fluid hasn't helped. I've looked for a fuse that might be the culprit, but none of them are labeled for the washer pump.

Any advice is greatly appreciated.

Best Regards,
Rob

does the pump run when you push in the stalk? Its a two position button though, pushing it gently only wipes, pushing it fully in engages the pump.

Thanks for the note, Z; the pump does not run - all I get is a single sweep of the wipers and then they go back to park. I thought I was jamming in the button pretty hard, but I'll have another crack at it.

Best Regards,
Rob

Pushing it in to the first stop causes it to sweep continuously as long as I hold it there, and pushing it to the second stop causes it to sweep only once then park; in neither case do I hear the pump running.

perchance you have been using windshield fluid which wreaks havoc on the sensor and clogs the pump? this is something which has been a problem for a few years. you may
want to web-browse your fluid brand/type

Thanks for the comment, Raymond.

I've been using the ubiquitous blue washer fluid that's available everywhere and which I've been using for years in my wife's S211 2007 E350T without any problems. The pump is not running at all when the button is fully depressed, so I find it unlikely that the problem is due to clogging.

Can anyone point me to where I can find the fuse for the pump motor?

Best Regards,
Rob

I mean, it takes less than 10 seconds to attach a multimeter and see if you have voltage at the pump when the button is pressed....if you do, the pump motor is junk. Why make life hard?

The pump motor is attached to the fluid reservoir, which on the W211 is buried down inside the right front fender; to access it, I need to jack up the car, remove the wheel, remove a half-dozen or so assorted fasteners, then remove the fender liner. You may be a more efficient mechanic than I, but this would take me far longer than 10 seconds.

On the other hand, checking a fuse would take me about 10 seconds.

You do know that fuses blow for a reason right? Let's say you found a blown fuse, is that the end of your diagnosis? Who's to say it doesn't blow again? Then what's the cause? Seized pump? Chaffed wires? Mouse damage? Magic? I wasn't trying to be a smart ass, but you seem to have taken it there. Let us know when you fixed it.

on my old W210 - I faced this issue and the entire tank was full of what I can only relate to as mineral salt dropout.

I found this very odd and actually fixed it just by accident.The coolant line coil that heats up the washer fluid was leaking from the O rings on its own thermostat. Causing coolant to seep in and react with the methanol in the fluid to disperse out the coolants silicated salts. (these salts had clogged the pump and burnt it)

The O rings fixed this for good. as I never experienced the same problem again till I owned it.