The difficulty is coping with DICE. For that reason I wouldn't recommend cutting any wires.
A brief description:
The motor current is switched via the wiper stalk. However the intermittent wipe and single wipe after wash signals are generated by DICE, which doesn't have the capability to sink the required current, so drives the intermittent wipe relay instead.
The suggestion of removing this relay makes sense. I would think it might work just by connecting the yellow wire of the controller to pin 3 of the relay base, and not bothering with the white or green. You'll need to connect the brown, red, grey and black as per diagram.