RADIATOR GP 4Q5699 - Caterpillar

Main Power Relay
Illustration 1 g01430986
Main relay magnetic switch circuitThe components of the main relay magnetic switch circuit are the key start switch, the main relay magnetic switch, and the idle timer/fire suppression loop receptacle.
Illustration 2 g01022428
Dash panel (1) Key start switch (2) OFF position (3) ON position
Illustration 3 g01430987
Cab (below rear arm rest) (4) Main relay magnetic switch
Illustration 4 g01022439
View of upper cab (cover removed) (5) Idle timer/fire suppression loop receptacleWith key start switch (1) in OFF position (2), main relay magnetic switch (4) is not energized and the relay contacts are open. In this condition, 24 volt power is present in circuit breaker 11, circuit breaker 12, circuit breaker 13, and circuit breaker 14.When key start switch (1) is turned to ON position (3), 24 volt power is supplied via idle timer/fire suppression loop receptacle (5) to main relay magnetic switch (4). Main relay magnetic switch (4) is energized and the relay contacts are closed. 24 volt power is now supplied to all circuit breakers.