Engine safety interlocks

[hwr]

Will not crank.. I think a safety switch is not engaging. I can hear brake switch clicking. I can short the seat safety switch. I can hear no click when disengaging the blade switch.
How do I trouble shoot the safety for the blade engagement?

 

[pile81]

What type of mower?

 

[hwr]

problem was alternator.. jumped with car and runs.. dies after about 20 min dead battery.