24 To 12 Volt Converter - jcb JS300 Service Manual

Component Location
The 24 to 12V converter module is located in the back of
the cab next to the main fuse and relay board.
Overview
The 24 to 12V voltage converter module provides 12V
power for operation of the radio, auxiliary power sockets
and HVAC unit.
Wires and Connectors
K Fig 19. ( T C-142)
– 24 to 12V - Radio
– 24 to 12V -
K Fig 20. ( T C-143)
The voltage is reduced by the voltage converter module
(C067) and gives out a permanent 12V supply on pin 4 and
a switched 12V supply on pin 5. Pin 3 is the earth wire for
the unit.
The24V battery supply connected via fuse 23 on the cab
fuse and relay board (C100 X4) to pin 1 on the converter
connector. A permanent 12V battery supply is then output
on pin 4. This 12V supply enables the radio memory
function (C057).
A second 24V ignition supply is fed from fuse 4 of the fuse
and relay board (C100 X4) to pin 2 of the converter
connector. A 12V ignition feed supply is then output on pin
5 to the radio ignition supply via the radio mute button
(C111). If the mute button is set to ON power connects to
the radio. The converter also has 2 grounds on pins 3 and
6.
There is also a 12V ignition supply to the two auxiliary
sockets (C163, C151) and HVAC unit (C072).
C-141

24 to 12 Volt Converter

Auxiliary Power Sockets
C067
Fig 18. Harness Connectors C067, C111, C151 and
9813/5100-1
Section C - Electrics
Cab Systems and Lighting
24 to 12 Volt Converter
C111
C151, C163
C163
C129480-C9.eps
C-141