1998 Vauxhall Astra wipers

Hi
i am having a problem with the wipers on my car. Its the 98 to 04 astra.
the problem is that the wipers dont work at all on intermediate or when I squirt the washers but work fine on normal and fast settings. I have tried the motor, relay and switch from a car that was working fine but it is still the same for my own car I was wondering if there was a secondary relay or is it to do with the timing module? Im not sure where to go with this because vauxhall dealer tells me it has to be the motor. If possible could I get a copy of a wire diagram to try and figure this out. Any help would be much appreciated