There is no separate brake switch on this mower as the two motion control arms safety switches are used along with a relay. The brakes are activated when when the control arm(s) are in the outboard park position. Each control arm controls the respective arm on that side hydro unit.
Well the component circled is a relay. Still a type switch but you won't find it shown in the IPLs but it is listed in details as PN 532109748. The IPLs will not show its location, just going have to trace the wiring harness to find it. I only got one customer with a Z254 and it hasn't been in the shop in four years. The motion control arms operates it when the arms are outboard (parked position). If either one of the motion arms switch should fail the mower will die when when in neutral non parked or forward or reverse. As depending how one of switches fail the starter solenoid (another type of relay to me) will not operate. Being a 40A relay the contacts should never get burned. But the safety takes several amps when place in park so their contacts do get burned when the ignition switch is in run position. The orange wire thru the safeties is the grounding circuit for the relay and the blue wire path is magneto kill circuit.
The solenoid next to the relay is the starter solenoid which they don't show any additional wiring for connecting to starter..
