Windscreen wiper motor mechanisms Question

[finch wxm]

Ive just connected my windscreen washer motor and mechanisms back in place. Ive noticed only two out of the 3 stalks located on the scuttle panel only rotate.

Is this correct ? as far as i can see i think only two are driven offthe wiper motor,is the third purely a support or doi have a problem.

I have lost the wiper arms and blades in my garage soi can just try themat the moment !