This looks to be the same fault as I am suddenly having on my `99 Megane.
Recently the front wipers started to work on their own when I started the car. I am able to control the wipers with the fan knob, there is no control when using the wiper controls. I noticed that sometimes the wipers would start, but this is purely do to with the positon of the fan control.
The heater fan doesn`t now work at all, but purely controls the wipers. If the wipers are moving and the wiper control is moved, the wipers stop. Turn the wiper switch to off, leave the fan control to full power, leave it for 30 seconds and the wipers are once again controlled by the fan.
I have a Haynes manual, but it is not at all clear when following the circuit diagram. I have been told it could be an earth, relay or
Any more thoughts please?