[Phantom]

You could use a windshield motor to do what you wanted. You would build the linkage just the same as it is for controlling one wiper, the only difference is you would need to extend the rod that is connected to the block.

Connect the motor and linkage to the block, get two momentary switches. Place the switches where the linkage will press the button only when it is fully open or fully closed. It will be easier if the switches are normally closed. Run the momentary switches to a three way switch (might have to use relays to handle the power). So now when you press the switch to open the motor will move till you release the switch or till the linkage presses the button cutting power to the switch. Now only the other direction of the 3way switch has power allowing you to close it.

I hope this makes sense.