Mk1 Yaris Washers Misbehaving

[Carole Heard]

I have a Yaris 1.0 CDX that I've owned from new in Dec 2000.

Some time ago, the washers developed an odd fault:-

When I washed the rear screen, the front wipers would wipe.

A couple of weeks ago the washer pump failed completely, so I replaced it with a unit off eBay. A bit of a pfaff but all sorted.

The new unit is very quiet compared to the original fit.

The rear wash/front wipe problem disappeared immediately after fitment.

Now it's back, but only intermittently.

My guess is that the front wipe is being triggered by a voltage appearing on the front wash supply line. It may be from back EMF from the front wash motor winding due to it acting as a generator, but why would it be intermittent?

Alternatively there's a low impedance between the two lines.

Any experts around who can point the way?

[Madasafish]

The washwipe switch may be faulty - it drives both sets of wipers .

[Carole Heard]

But surely there's a couple of switches?

The rear wash is a knob on the end of the stalk whereas the front wash is triggered by pulling the stalk towards you.

[Geoff Peace]

But surely there's a couple of switches?

The rear wash is a knob on the end of the stalk whereas the front wash is triggered by pulling the stalk towards you.

Very true but in cases like this, it is often a poor earth connection which causes the problem. The current tries to find its way to earth, often through another part of the wiring harness. I would check the wiring on the wiper harness and its connector.

Regards Geoff Peace.