Revision Date
– 22/12/2014
page 27
8.2 Test compressor control unit
– 12/24V DC
Purpose:
To verify the correct operation of the compressor control unit on 12/24V DC.
Approach:
This test will isolate the compressor control unit from the external control circuit. The
external control circuit includes the main circuit board, the control panel circuit board, the
thermistor and the wiring loom.
Test pass:
The compressor runs. In this case the main circuit board, the control panel circuit board, the
thermistor or the wiring loom are likely to be faulty.
Test fail:
The compressor does not run. In this case the compressor control unit is likely to be faulty.
It is also possible that the compressor could be faulty but this is EXTREMELY unlikely.
Procedure:
See below
Disconnect all power leads from the back of the
fridge.
Remove the rear cover (refer to section
Identify the compressor control unit.
Disconnect the push on connectors from terminal
“T” and the lower terminal “C”.
NOTE: There are 2 terminals on the control
unit that are
labelled “C”. Only
disconnect the plug from the lower “C”
terminal.
Apply 12 or 24V DC to terminals “+” and “-” on the
compressor control unit.
Use a DC voltmeter to confirm that the polarity of
the 12 or 24V DC supply voltage across terminals
“+” and “-” is correct.
NOTE: The compressor control unit has
polarity protection and will not work if
the polarity is incorrect.
NOTE: The compressor control unit and
digital display will not operate if the supply
voltage is below approximately 7V DC.
ARB recommends that the supply voltage be
applied through the DC power socket in the back
of the fridge and not directly to the control unit.
Compressor
control unit
Use lower
Terminal “C”
Terminal “T”
Do not use top
terminal “C”
Connection
to 12/24V DC
“-”
“+”
