Luddite,
Many thanks for the information. I did know about the wiper motor arrangement but forgot about it many years ago, so your comments are very pertinent. I have been assuming the problem lay with the wiper on/off switch but I think a bit of investigation into what happens in the motor when switched is warranted. I have a lot of experience with industrial wiring and what happens in cars is often a surprise to me. So I thought the motor was unlikely to be the culprit but it is now worth investigating.
In industrial motor controllers it is not unusual to have the motor terminals shorted (often via a low value resistance) when switched off and this uses the generator mode of the motor to stop it quickly. However I do not see the need in this application.
I will post an explanation as and when i find it (he said with hope).
Thanks again,
David
