Windscreen washer pump

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markhowes
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The rear window washer has stopped working on my 463 G300. The front washer is fine.

It would help if I understood how the pump works as there are two outlets from the one pump - I assume that one outlet goes to the front windscreen and the other outlet goes to the rear.

But the pump only has two electrical connectors on the top so what causes the water to go to the rear rather than the front?

Is it that the pump works in reverse to feed the rear? Or is there a valve somewhere in the water circuits that stops water going to front or rear depending on which switch is operated?

Anyone know the answer?

 

Jdring
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Re: Windscreen washer pump

Oh, thats a good one.  I have simlar with a 460, and assume the pump might be the same.  I will dig around.

gav.helme
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Re: Windscreen washer pump

460 has seperate pumps for front and rear 

JASONGDS
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Re: Windscreen washer pump

The larger of the two pumps does the headlight washers, as far as I know the   smaller pump feeds the front and back windows, can you hear any pump running when you press the switch for the rear window?  

markhowes
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Re: Windscreen washer pump

I hear the pump running when the front washer operating but no pump running when I push the rear windsreen washer switch.

What I can't work out is how does the one pump operate both front and rear given that there are only two electrical connectors?

 

 

 

gav.helme
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Re: Windscreen washer pump

The switch when pressed gives power to the pump?

Be that front or rear

Might struggle if both are pressed together 

But you might struggle too!!
 

Still think it's the switch or wiring to it

markhowes
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Re: Windscreen washer pump

Thanks Gav.

It would help if I knew what was supposed to be happening. There are only two electrical connectors on the one pump so what makes the water go to the front or the rear?

Does the pump operate in two directions - so positive and negative elec feeds depend on which switch is operated)?

The pump is plastic and doesn't appear to be earthed (other than via one of the two connectors on the top)

Will have another go with the multimeter when the weather gets a bit better.

 

JASONGDS
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Re: Windscreen washer pump

I think that's the way it works, you could just swap the wires around see if rear washer works when you press front stalk?or use a multimeter and a assistant? 

tyrekicker
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Re: Windscreen washer pump

hello,

 

I have just replaced my washer pump for the reason of  front screen not working.

plus some fool at  a garage broke the pump and lost the internal impeller !

there are two pumps on the W463 one for head lamps 

one for the font and rear washer - firstly check the rear wash pin hole is not blocked - use a pin to clear the spray hole ! (we did that last !)

then test the motor is running with  power from another supply,these old car terminals oxidise and lose connectivity

clean up terminals or fit new female connectors and it should work (test before refitting)

note; be careful when removing as these parts can become brittle 

If the motor is not working - you can fit another from a different vehicle as they are all the same size

When you find an orginal one,you can swap back 

fraj
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Re: Windscreen washer pump

          Make sure that the problem is not a leaking water pipe.   They have been known to leak near the hinge side of the rear door up at the top.   If that happens you will get a bad case of "tin worm" just inside the lower near side door shut.  I have that problem,  It is not a pretty sight.  

I hope you find it is only electrical.

Regards,

              Alex.

markhowes
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Re: Windscreen washer pump

Look what I've invested in. I will report back once I've found time to fit.

 

markhowes
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Re: Windscreen washer pump

So, I now have fully functioning high pressure headlamp washer. smiley

Unfortunately the rear windscreen washer still not working. More investigation needed.

markhowes
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Re: Windscreen washer pump

Now have a new rear windscreen washer switch on its way to me.

I'm sure I've done it before but can't remember how. Does anyone know how to get to the switches on the centre panel on an early (1991) 463 G300?

It's possible that I'm remembering from when I had to do it on my previous car (MB 300TE). I think on that occassion it was quite compliacted and involved taking off the steering wheel so  if someone knows for sure or can point me in the right direction that would be great.

 

 

JASONGDS
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Re: Windscreen washer pump

You have to remove the steering wheel to remove the long wooden  strip, ( this is easy to break) some screws behind that, can't remember if screws at the bottom,  go easy on the switch panel, as not much free/ extra wire onthe diff lock illumination,  double check everything works before reassembly!