Have a ridding mower with briggs 12hp have not power to starter. Figure it must be a safety switch. How do you by pass them to check to see if they are bad>? Not to eliminate them. The blade one has 4 wires and one is hot and in the start position the other one turns hot but the 2 that go to seat switch there is no power? Help

Hi,
Sounds like the switch you referenced is working. The solenoid has two large posts for the high current starter circuit(big wires) and one or two posts for the trigger circuit(small wires.) Check to see it there is power to the trigger circuit with the red wire(usually) in the start position. If so and there is a black wire trigger circuit, check it for ground(usually not such a circuit on a Craftsman.) If power gets to the solenoid, then it is bad, a common device to fail.
Peace,
Clarke