My rear wiper works when the car is first started but after a few wipes it stops. I conclude there is not a problem of supply like broken wires as there is always feed. I suspect the timer control is the problem and it warms when the ignition is switched off. I know there is a thermal cut out on the motor but the symptoms don't point to that. Has anyone suffered the same problem and does anyone know if the timer is part of the motor assembly or separate?

Do you mean theres a permanent feed? It shouldn't have.

If it doesn't have a live feed I am puzzled. From cold if you switch the wiper on it works for a while then stops which suggest a motor cut out, however, if the wiper is not switched on until the car has been running for a while it will not work. This led me to think there is a feed to whatever adjusts the frequency and if that is in the motor it would indicate a feed to that?

Sorry, I meant it shouldn't have a permanent live at the motor with the switch off !

At first thought I would suspect the switch/stalk or maybe its module :unsure:

Do you know if the timer is in the wiper assembly. I am thinking if it is the problem I may bypass it.

I have had exactly the same problem for several months and have made the same conclusions. I cannot find a wiring diagram that shows whether there is a separate relay or timer as I like you wonder if it is elsewhere it may be an economical fix.

Mine has now packed in completely so I have the incentive to sort it and wondered if you finally managed to figure it out.