According to the Lucas pin out for a 35927 switch the following connections are made:
Position 0 (off) Pins 1, 2, 6 & 7
Position 1 (slow) Pins 1, 4, 6 & 7
Position 2 (fast) Pins 1, 4, 7 & 8
In order to make the motor work as required you need to connect the switch like this:
In position 0 the slow speed must be connected to the park switch only
In position 1 the slow speed must be connected to the power feed and the park switch and fast speed disconnected
In position 2 the fast speed must be connected to the power feed and the park switch and slow speed disconnected
The only way to wire the 35927 and achieve that is this:
Pin 2 the park switch (connected via the brown/light green to pin 2 on the wiper motor)
Pin 4 the power (connected via the green wire to the ignition feed. Note that the wiper motor must have an ignition feed to pin 4 to make it park)
Pin 6 the slow speed (connected via the red/light green wire to pin 5 on the wiper motor)
Pin 8 the fast speed (connected via the blue/light green wire to pin 3 on the wiper motor)
All of the above assumes that the wiper motor park switch and brush plate are connected correctly and the switch has not been 'helped' internally by someone.....
Which isn't always the case....
On the 14W motor there are 3 wires from the brush plate Red, Yellow and Blue.
The Blue is the earth and should be connected to pin 1 on the park switch/connector assembly on the motor
The Yellow is the fast speed and should be connected to pin 3 on the park switch/connector assembly on the motor
The Red is the slow speed and should be connected to pin 5 on the park switch/connector assembly on the motor
You should check that your switch operates as described above with a continuity tester and the the motor is wired correctly otherwise you will be chasing the circuits around for ever.
Good luck!