Strange windscreen washer problem

[Nautilus]

Hello everybody

My windscreen washer pump decided to go on a strike last Sunday - it squirted washer fluid on the rear window but not on the windscreen whatsoever. Electrical circuit worked, since the wipers started, but no fluid came out. Pump did not buzz.

Since this happened on a very muddy day, went to the nearest workshop. They checked the pump and connections, pulled out the plug and measured - one pin had 13-13,3 volts and worked normally (rear), the other had just below 11 volts and did not allow the pump motor to run (front). Tried a spare pump, same thing - squirted only to the rear. Fuses on both circuits were OK.

Just what kind of an electrical bug can make the pump work only on a single pin?...

Thank you,

~Nautilus

 

[nennokair]

Definately no blockages? dont know if this would stop the pump operating though.

i know youve tried a spare pump but there may be some sort of valve that switches direction depending on whether the front or back is pressed. may be clogged.

 

[Nautilus]

Tried also both original and spare pump "dry", unconnected to pipes, still the motor doesn't turn towards the windscreen, only to the rear. And as far as I know, an electric motor which gets 1-2 volts less still turns, but much slower.

~Nautilus

 

[Muttley]

Check the current drawn in both directions. It sounds like a switch fault, or a bad connection somewhere (pump or switch is favourite). If a contact is corroded there may be enough conductivity to show voltage, but too high a resistance to let much current flow. You've pretty much eliminated the motor as an issue.

 

[Nautilus]

The switch (stalk to the right of the steering wheel) operates the windscreen wipers when pulled, but pump doesn't turn.

~Nautilus

 

[Muttley]

And.....?

Wipers are on a relay, powered by a separate connection to the battery. The switch only has to provide triggering, very little current drawn and only briefly.

The washer pump is powered directly through the switch, so high-resistance contact somewhere is still the most likely explanation.

I suppose it's just possible that the wiper relay is faulty and pulling the voltage down on the windscreen wash/wipe contact. Try removing the relay and see if the pump will operate then.

The hatchback wiper has a separate, selfcontained relay.

 

[Nautilus]

Where is the wiper relay in the dashboard?

Later Edit: since today:
- operating the switch to the windscreen does not turn the pump, but operates the front wipers;
- operating it to the rear window does turn it, rear wiper starts, but no fluid comes out of the rear, instead it trickles slowly from the front sprinklers

~Nautilus

 

[Nautilus]

Problem solved by itself after some irritating months

~Nautilus