Mower will not start by key, just clicks each time I turn the key. I can hot wire by crossing the solenoid, runs fine. There are 4 safety switches that I know of, seat, reverse, blade, brake. Seat looks fine. Reverse also looks good. If I sit in the seat and put it in reverse, turn key, no clicking. I can see the brake switch but can't get to it easily. If I donot put the brake on, no click when I turn the key, brake on, click. Same with blade, blade on, no click, blade off, click... so, my question is, have I proved it is the solenoid or have I proved nothing? For 12 bucks... it's probably worth the try since it is seven years old. Thoughts appreciated, thanks.

Since you've bypassed it and it starts, I'd say yes, you found it. :)

Yep, sounds like the solenoid... the switches would cut the power, so no clicking.

Yup... that was it, thanks!