Chapter 3 N39453
Page 38
Engine wiring harness (optional equipment)
The engine wiring harness is designed to convey information to and from the engine control panel. Within the
harness is a circuit breaker and a negative earth fuse to protect the wiring in the event of a short circuit as well
as control relays.
Access to the circuit breaker is from the outside of the control box. This can be used to isolate the control
system during servicing. The 10A breaker protects the control system to the panel(s). Interuption of this will
inhibit the control panel and thus the starting of the engine.
The momentary connection of the negative line to earth is protected by an 80A breaker located within the
enclosure adjacent to the 10A breaker.
Within the control box are four relays. Three are high current relays designed to control the operation of
the starter and the glowplugs. During the operation of the glowplugs a negative earth relay momentarilly
grounds the engine to negative. The fourth relay controls the fuel lift pump stop solenoid and cold start advance
solenoid.
The fuel is delivered to the fuel injection pump via an electric fuel lift pump. This commences operation in
tandem with the stop solenoid when the engine circuit switch is operated on the control panel.
Engine circuit variations due to system damage
24V engines - Engines with 24V systems will have tted a 24V to 12V converter (unit coloured black) to
operate the 12V fuel lift pump.
Care should be taken to ensure that there is adequate ventilation around the voltage converter to ensure that
it does not overheat.
Caution: On no account may any load be placed on either the inverter or converter as this may cause the unit
to fail.
To Next Page
Loading...
