I have a 1960 Triumph TR3a which has one-speed wipers that just move the water around. I decided to put in two-speed wipers using the Lucas motor from an original Mini. The connections are power, low-speed, high-speed and park. My question is do I need to earth both low-speed and high- speed to run the motor on high, or only high-speed connection? I know it runs using the high-speed connection only but am not game to use both in case I let the smoke out.