Wiper switch

[Numplumb]

Hi has anyone had any problems using the wiper switch on the Mazda column with a different wiper motor?.
I have a wiper motor from a MGB and can't get it to work from the Mazda wiper switch, I've found a thread with a diagram showing how to test the Mazda switch for continuity but the connections only work if I swap the +v and the ground, when I connect the wiper motor with these wires swapped it will work on slow speed and fast speed but won't turn off, I have tried two wiper switches and they both do the same.

Regards Mick.