All those switches are very simple NO ( open circuit with the plunger out ) which is what yours should be or NC normally Closed with the plunger all the way out
Original switches are usually different colours but the after market ones look identical .
Your problem however will most likely be the seat switch.
Power goes from the red wire to the brown wire at the key switch when the switch is in the Start position.
It then passes through the PTO switch changing colours to Brown+Yellow. which is NC
Then passes through the parking brake switch changing colour to Brown + White. which is NO
from here it energises the the starter solenoid
So if it does not crank, pull the plug off the back of the key switch & jump red to brown
Engine cranks = faulty key switch
Then pull the plug off the back of the PTO switch & jump Brow to Brown / Yellow.
Engine cranks = faulty PTO switch
Finally pull the plug off the brake switch & jump brown/ yellow to brown / white
Engine cranks = bad brake switch
If it still does not crank jump the red directly to the Brown / white terminal on the starter solenoid
Solenoid klacks = wiring along the brown wires .
Solenoid does not Klack = bad solenoid ( includes poor ground connection )
Use a heavy jumper to go battery + to the starter motor
Starter spins = bad battery cables
Starter does not spin = bad starter or ground cable
Final test is to jump battery - to engine
starter cranks fine = bad ground strap
Starter does not crank = bad battery
To confirm bad battery do the final two jumps off our car, truck or with a known good battery .
All of the brown wires should show battery voltage is their connections are good .
ou will find the wiring diagram in the back of the parts list, a free download from Gravely .