Currently, I am working on the wiper motor. This Lucas DR3 is really fascinating with it's feature that in the park mode the wiper turns back not only to the normal park position but a little bit further by switching the rotation of the engine.
This DR3 unit works together with the Lucas PRS7 switch. The "AC Cobra Chassis Construction Book" contains at page 50 a wiring diagram for both units. That's fine but it describes which color (of the DR3 unit) must be connected to which number of the switch. My wires had all the same color: something between brown and mud black. I opened the unit and try to understand how this unit works.
Based on this quite useful link
DR1 & DR3 wiper motor I made my own diagrams. What is different is the swaping of the red and brown wire and the connection to the switch are a little bit different.
We can see that in the park position the polarity of the coil field is switched, the polarity of the armature is still the same.