Wiring gremlin: Rear wiper controlled from light switch

[Quattro100]

I have a problem with the wiring on my 92 8v.
It started in the cold weather last week.
The car started the day well. But the first hint of trouble was that I became unable to switch the front wipers off.
The car was then left in the sun and when I returned at lunch no problem everything worked fine.
That evening however I became unable to switch the rear wiper off.
I worked it out to be the light switch. If the lights were off then everything worked fine, but when the lights were on the rear wiper would be constantly in operation.
I have now disconnected the rear wiper motor, as removing fuse did not have any effect.
Any ideas where to look, possibly a short on the fuse board.
Thanks Will

[Thom89]

Broken wire syndrome!   Open your tailgate, left hand side, wires come through the roof panel, into the tailgate, pull back the rubber sheathing, and you will find broken wires! what's happening is that your broken No plate wires, are shorting with your broken rear wiper wires, hence the fault, easy fix though, re solder wires back together, then heat shrink,,job done
Tom

[Quattro100]

Tom,

Thanks, I will be onto that this afternoon.
regards
Will

[Grazy]

Did you fix it Will

  Graeme 

[Quattro100]

Greame,
I have not yet had the chance to look. Unfortunately work always gets in the way of pleasure.
Thanks for our help. I will let you know when I have looked.
Will