I'm not convinced it's the switch unless it's just corroded pins on the switch receptacle, a faulty terminal connection or the start winding switch is welded shut causing the overload to trip. Also possible the motor centrifugal mechanism isn't working. You say you checked the overload and it was ok. Did you check it immediately after the motor stopped before the overload has a chance to reset? If you let the machine alone after it cuts off, will it start again after a while on it's own? Anyway, the current in the blue wire from the timer flows directly to the blue wire on the motor. It does not go through any contacts. That only occurs when low speed is selected on multi-speed motors. This washer has a single speed motor. You may have a bad connection at the motor connector or switch connector or possibly a faulty timer. If the motor switch is faulty, it has to be a connection problem at the plug/receptacle, not inside the switch unless the problem is with the start contacts as I mentioned. Let us know what you find.
Eric