Rear screen wash comes out of front nozzle... (a-class)

[mat8iou]

In the past, when I used the rear screen wash button on my A160 (1999), it came out of the rear nozzle fine, with a slight trickle out of the front nozzles sometimes.

Since yesterday, when I press the rear wash button, nothing comes out of the rear nozzle & a lot comes out of the front nozzle.

The button for the front screen wash works as expected.

Does anyone have any suggestions on what is going on here, or what the best approach is to try & correct this?

 

[brandwooddixon]

This is just a guess.

Perhaps the A class uses one washer pump and a valve to redirect washer fluid between the front and rear screens, rather than two separate pumps.

If this is the case then I would think that the valve has either become clogged and stuck or it has failed electrically.

 

[mat8iou]

Thanks for the suggestion.

That kind of makes sense.

I'd have thought that the slight trickle before from he front suggests a clog or blockage is more likely? With an electrical failure, I'd have thought that it would be all or nothing.

 

[brandwooddixon]

Yes - probably clogged.

The valve may be part of the pump - best to check to see how many squirter pipes run from the washer bottle.

 

[wireman]

Some Hella pumps are run in reverse to pump out to a second outlet for the rear wash, if the rear tube is blocked or is crushed in the loop from body to rear door the water comes out the wrong hole and the front gets it.

 

[Daeths]

had the same problem and it was the blocked water jet on the rear. rather than a pin i got some wire stripped it and cut back leaving 3 strands. twisted ti give rigidity and gently poked away. this method allows you to get past the nozzle and into the pipe behind hit. a pin just goes as far as the nozzle.

 

[mat8iou]

Thanks for all these thoughts.

I'll have a look at the nozzle & see if I can unblock it. I had a look at the pump this morning & it definitely has two pipes coming out of it going to the front & rear. I tried re-seating the electrical connector on the pump, but as expected that made no difference. When I try it now without the car running, I can hear it makes a different noise to normal when I try & use the rear wash.

Time to find some thin wire...

 

[mat8iou]

Ok, I've tried using a piece of wire to clean it. I can push the wire in about 1 1/2 inches before it gets caught against something & doesn't want to push any further.

I've tried the screenwash again & there it still isn't working.

How far did you push the wire into it when you cleaned yours?

 

[Ellsy Tanners]

The supply pipe for the rear often pops off on a a-class. pull down the pannel at the back of the headlining and check there. There is a joining piece that comes apart.

 

[Daeths]

The supply pipe for the rear often pops off on a a-class. pull down the pannel at the back of the headlining and check there. There is a joining piece that comes apart.

If the pipe had popped off you would hear your boot filling with water and see the water (from my 1st hand experience)

With my hose detached I ran the pump too flush out any debris/bits. I then poked the wire in the hole wire the pipe goes and then from outside via the nozzle jet.

 

[mat8iou]

That was my thinking regarding the supply pipe coming off (haven't had a chance to look at that bit yet). If it had come off, then the fluid would just be disappearing somewhere into the boot door - not coming out of the front nozzles? Unless it is possible for the pipe to be pinched somewhere rather than to have come off?

 

[mat8iou]

At last, following many weeks when I haven't had the chance to look into the problem, I have managed to solve it.

I looked under the bonnet during the middle of the day (previously I had only managed to check in the evening) & saw straight away that there was a loose pipe that appeared to be the one for the screen wash. Activating the screenwash confirmed this, as fluid was dripping from this pipe.

Having re-connected the pipe a firmly as possible, the screenwash is now working properly again. I'm still confused though as to why the pipe being disconnected would also lead to water coming out of the front washers when I pressed the rear wash button - it has stopped now that the pipe is reconnected.