C5 Mk1 EState - Rear wiper fault

[Trainman]

Been talking to the "Old Man" tonight and he mentioned that he has an intermittant fault with the rear wiper, basically the rear wiper works of it's own accord and for no apperent reason, he can open the car and the wiper will work........ he can switch on the hadlights and the wiper will work....... he can open a window and the wiper will work......

There again the following day nothing out of the ordinary, normal service is resumed

I suspect it's a bad earth somewhere but any ideas where to look first?

[SaabC5]

I had a 307 Pug with the same fault, knowing they are parent companies and share many components i suspect its the same fault. In the Pug it was dry solder points in the control module attched to the wiper motor. The wiper would work whenever you opened a door or tailgate and occasionaly on its own without any prompting, it would often fail to work on the proper command as well!

[Trainman]

I shall have to dragg the soldiering iron out then, joy

Thanks though its somewhere to start