defender/disco rear wiper motor wiring

just got round to looking at my rear wiper on my fender 110.

Identified the wires from the fender ok, bit of a puzzle to the motor.

the motor has 3 wires, white, brown and black.
black is earth, however cant figure out what the other 2 are supposed to be, when connected, they both just run the motor constantly.
presumably one should be perm live, the other switched, Im also guessing that the park switch is goosed...

any help on how to solve this, at the moment, Ive connected the earth and the brown (Ill park it manually)
also, on the side of the motor is a "bulb" it looks like its supposed to be an intermittent switch (looks like a bi-metallic strip in it)

I said fender/disco as the motor is a used unit that came with my motor, but has disco rear wiper written on it in breaker pen, hence posting here, not fender...

Looking in my disco haynes manual at the wiring diagram for a pre95 rear wiper motor:

WHITE = Permanent live from fuse B6 10Amp (disco) - probably for the park system
BROWN = Rear wiper switch also from fuse B6 10Amp (disco) - for operation
BLACK = Earth

Remember that rear wipers only have 1 speed

Daz

cheers, looks like the park swich has had it, not bothered about 1 speed, the fact it works at all is fine.
it had been wired up incorrectly that burn the switch out (wrong fuse in there too!!) so got another switch, tested motor, all works fine except for the park bit. will have a look at the old motor, see if the park switch is the same, failing that, sod it , it works!!!