bypass ignition switch

[oddjob1]

Hi
2 wires from ignition switch came off so cut other off and wired 2 into a seperate switch ( keyless )
Works fine but would like to know what the other wire does?

[oddjob1]

sorted now i think..power to the fan..had to change thermostat and housing..bit of a mare..got a slight leak on hose..probably put a hole in it when dismantling..i fix it another day...too hot