[EQA-S.oz]

The season has finally broken (farmer's terminology) in our part of Australia, which has caused me to use the EQA's windscreen wipers for the first time.

Nothing unusual in operating the wipers, but I've searched high and low for a method to stop the rear window wiper operating automatically when the front wipers are on and I'm reversing. A quick Google search has identified comments from other Mercedes owners who share my frustration at not being able to switch the auto rear wiper off - except when I want it to operate. I've had other cars with this sort of function, but they have had a menu setting which allows you to either opt for automatic rear window wiping, or not; i.e. it's fully switchable.

My immediate solution - in light rain - is to use the 'single wipe' function (press the end of the left-hand wand) before reversing, then, after reversing, either another press when D is selected, or switch to one of the auto settings. (I tend to use the single wipe function in drizzle or very light rain, because I find that the rain-sensing wipers tend to be a bit too sensitive.)

The other option, I guess, is to remove the rear wiper fuse. I rarely use a rear wiper, so that's a possibility, but I haven't delved into the fuse box to see if it's a stand-alone fuse.

Any other thoughts on this?

 

[EQA-S.oz]

Pursuing my "other option", I've delved a little further into the EQA's fuse system. The attachment - the first two pages of which are a scanned copy of the fuse location leaflet found in the fuse box under the bonnet - informs me that the fuse for the rear wiper is No. 106 and it's located in the fuse box in the passenger's foot well. Having located that and removed fuse No. 106 (see red circled fuse in the third page of the attachment), I turned the ignition on and pressed the rear wiper 'one swipe' button - and it did one swipe. Clearly, this isn't the correct fuse.

Can anyone enlighten me which is the correct fuse?

 

[FDR]

I haven’t noticed whether my car does this with its wipers, I need to get out in some rain to see.
I note with regard to your fuses there are three fuses listed for the front wipers, do any of them affect the rear wiper?

 

[EQA-S.oz]

I have done some more research and discovered that the fuse which supposedly controls the rear wiper is part of the CBC / SAM and Central Locking circuitry (see attached pdf).

I have referred my objective and my findings to the local dealer. I hope to report information from them soon.

I haven't asked your specific question, FDR, but perhaps the dealer's response will shed some light on it. I suspect one or more of the three fuses relates to the rain sensing system; perhaps another covers the front windscreen washers. An accurate wiring diagram would be helpful!

Having noted that Fuse No 106 performs other functions, I've replaced it prior to driving the car.

 

[FDR]

My theory (and I could be totally wrong) was that if the rear wiper is operating when its switch is off but the front wipers are on, the power must be coming from the front wipers bypassing the rear switch, so it could also be bypassing the rear fuse.

 

[FDR]

Possibly a better solution, rather than pulling a fuse (as there are a lot covering more than one circuit) you could find the wires supplying the rear wiper and instal an on/off switch? Perhaps near the motor?

 

[EQA-S.oz]

My theory (and I could be totally wrong) was that if the rear wiper is operating when its switch is off but the front wipers are on, the power must be coming from the front wipers bypassing the rear switch, so it could also be bypassing the rear fuse.

There's some logic to that!

My test involved switching the rear wiper on using the switches (buttons) on the left-hand staIk. Perhaps that circuit derives power through one of the front wiper fuses, whereas the 'reverse gear activation (with front wipers operating)' triggers a relay which completes a power feed through fuse No. 106. I'm guessing!

Possibly a better solution, rather than pulling a fuse (as there are a lot covering more than one circuit) you could find the wires supplying the rear wiper and install an on/off switch? Perhaps near the motor?

That seems like a good solution to me, but I'm wary of fiddling potentially voiding the warranty should anything - even something unrelated to the wipers - play up.

 

[FDR]

You could always just pull the wiring connector off the motor and tape it up, that way if anything went wrong you could easily reconnect it and there would be no sign you had interfered with it. It would also leave no trace if you came to sell the car. The only reason I suggested installing a switch would be if you decided for some reason you needed to quickly get the use of the wiper.

 

[EQA-S.oz]

Food for thought. Thank you, FDR.

 

[EQA-S.oz]

Another option: remove the rear wiper arm from the drive spindle.

 

[Parkwood]

Just confused as to why this upsets anyone? If you are reversing then you want clear vision surely Even if using the camera. I know it is a subjective matter but just interested in why it is not wanted as for me it is something I appreciate and like and I would be very annoyed if it was removed.

 

[EQA-S.oz]

I'm sure many people would be with you on this, Parkwood.

Where I live, dust and other filth - which chooses to reside on the rear window - is more common than rain. The following circumstance is the one which bothers me: rear window hasn't been cleaned of that filth; there's misty rain and I need to reverse. The rear wiper starts in concert with the front wipers and the filth plus moisture creates a form of grinding paste. In the event of misty rain, you can dilute the paste - and eventually clear it - with the rear windscreen washer, but by then the muck has done its damage.

The "damage" is possibly more imagined than a real issue; it simply annoys me, just as the absence of a rear wiper would annoy you.

For the rear view, due to many years spent driving vehicles without a centre rear vision mirror, I tend to use the door mirrors (and the camera).

The thing I find frustrating is that I've owned several vastly cheaper cars which have provided the option of temporarily disabling the reverse-linked wiper function. For some reason Mercedes doesn't see fit to do so.

 

[Parkwood]

I'm sure many people would be with you on this, Parkwood.

Where I live, dust and other filth - which chooses to reside on the rear window - is more common than rain. The following circumstance is the one which bothers me: rear window hasn't been cleaned of that filth; there's misty rain and I need to reverse. The rear wiper starts in concert with the front wipers and the filth plus moisture creates a form of grinding paste. In the event of misty rain, you can dilute the paste - and eventually clear it - with the rear windscreen washer, but by then the muck has done its damage.

The "damage" is possibly more imagined than a real issue; it simply annoys me, just as the absence of a rear wiper would annoy you.

For the rear view, due to many years spent driving vehicles without a centre rear vision mirror, I tend to use the door mirrors (and the camera).

The thing I find frustrating is that I've owned several vastly cheaper cars which have provided the option of temporarily disabling the reverse-linked wiper function. For some reason Mercedes doesn't see fit to do so.

Thanks for taking the time to respond and I can entirely understand your reasoning😉living in Normandie dry dusty weather is a rather rarer occurance I suspect than you experience though we are facing a drought yet again this year and this week another unusual period of excessively high temperatures. For sure whatever the cause climate change is now tangible.
I also take you point re the on off switch. My bet would be that the engineers in Stuttgart (another damper climate than yours) just did not even think about the possibility of people not wanting it grinding through a dusty layer.
It makes one wonder how much the global brands take any input from those living in climates that are not similar to their own?
Forums like these are good as we can all share experiences and also learn about the differences which are just as interesting.

 

[FDR]

I think the mucky rear window problem is worse on the EQA than my previous car (Seat Ateca), possibly due to the aerodynamics of the car I find I need to use the rear wiper far more than I did on the Ateca. Rain doesn’t clear so easily without wiping and dirt seems to accumulate more.

 

[SkiSoFast]

Or you can try this:

KUFATEC

With this dongle it is possible to prevent the automatic rear wiper in the rain

www.kufatec.com

 

[EQA-S.oz]

Thank you, SkiSoFast.

There must be sufficient demand for temporary deactivation of the automatic rear window wiper to justify developing and marketing this product - which makes one wonder why Mercedes Benz doesn't do the same as many other manufacturers and include the function in the vehicle's owner/operator-accessible settings. Please excuse the cynic in me, but maybe they see an opportunity in offering this device for sale through their spare parts departments - complete with MB logo - for say double the price and charge who knows what to fit it.

Thank you again, SkiSoFast, for letting us know about this product.