Do you have rain sensor? The following is applicable to wipers without rain sensor, not sure about operation of cars with the option, but would think it's going to be similar.
Are you trying to use them with one of the front doors open? They have a built in sensor that prevents them from operating if you are, thus avoiding anyone getting water from the screen thrown at them when entering or exiting the car.
If you are using them on the first constant wipe speed, they automatically revert to intermittent wipe when stationary.