Bizarre wash/wipe fault

Oct 13, 2004 10 Replies

The windscreen washer on my '84 Porsche944 has developed a strange fault. When I pull the stalk forward to spray the windscreen, the wipers go but no water comes out. I've tried changing the washer pump which had no effect. I then connected a multimeter in place of the washer pump and found that I get 12V whenever I pull the stalk forward but then when I connect the pump to the wires nothing happens and I don't get anything on the meter!! Any ideas?? TIA


-- David Speir (remove NO.SPAM to reply)


The message from "David Speir" contains these words:

That sounds like there's a high resistance somewhere. It'd read as 12V until you put some load on it and it'll drop like a stone.

In news: snipped-for-privacy@0007148297.gst-group.co.uk, Paul Cummins decided to enlighten our sheltered souls with a rant as follows

Take it to your local VW dealership, it's probably the same set up on a Scirocco...

Try cleaning the contacts on the connector to the wash motor.. If you have power to the motor you would hear the pump trying to operate. If you have power then disconnect tubing and try a gentle blast of compressed air to clear any blockage.

"SteveH" wrote

Quiet tipoman!

Douglas

Definately a high resistance in the feed or the earth. Check the earth first by touching a wire from the negative or body to the battery earth. If that doesn't work, do the same for the positive feed.

I'm not so hot with the electrical side of things. Can you explain how to check for the resistance in idiot terms...? TIA

David - what's happening is that at one of the connectors, there is enough of a connection for the voltage to pass through, but when the pump tries to draw any meaningful current, the voltage at the pump drops to zero. You can confirm this by putting a voltmeter on the pump connections with the pump still connected and operating the switch. If you're not sure, I'd get an auto electrician to have a look - it shouldn't be too expensive - the worst case is probably the switch.

Are you saying the pump isn't working also? or is it a case of the water isn't being pulled through the pipes? Bill

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