Revision Date – 15/07/2020
page 28
8.3 Test Compressor control unit – 12/24V DC
WARNING: This test should only be performed by a licensed electrician.
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 remaining fridge electronics
including the main circuit board, control panel circuit board, thermistor and wiring loom.
Test pass:
The compressor runs. In this case the main circuit board, control panel circuit board,
thermistor or wiring loom are possibly 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.
Disconnect all power leads from the back of the
fridge.
Remove the front cover (refer to section
Identify the compressor control unit.
Disconnect the push on connectors from
terminals “T”, “P” and “C”.
Apply 12 or 24V DC to terminals “+” and “-” on the
compressor control unit.
ARB recommends that
the supply voltage be applied through the DC power
socket in the back of the fridge and not directly to
the compressor control unit.
Use a DC voltmeter and confirm the polarity of the
12 or 24V DC supply voltage across terminals “+”
and “-” is correct.
Connect between terminals “T” and “C” using a
short length of wire as shown.
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
7VDC.
NOTE: The connecting wire should be
terminated with either push-on
connectors or spring loaded clips
suitable for good contact with the
terminals.
Compressor
control unit