Norcold DC440 - Trouble Shooting - Procedure A; Compressor Not Running Diagnosis

3
Figure 1 - Temperature Control
Figure 2 - Power Supply
Note:
If 10 Amp fuse is blown, check wiring of vehicle
Trouble Shooting - Procedure A
Red
TP3
Brn
TP1
Blk
TP2
Yel
Org
ART01190
Thermostat "ON" Compressor does not run
Is Temperature
Control LED on?
YES
NO
Measure terminal
voltage of Temperature
Control between
TP1 & TP2
DC 0 V
DC 5 V
DC 2 V
Short Circuit
Power Supply
Failure
Normal
Change
Temperature
Control
Change
Power Supply
See Procedure B
Good
Check DC Fuse
Bad
Replace fuse if defective
10A (DE/DC)
8A (MRFT)
See Figure 2
Compressor runs
YES
NO
OK
Measure
terminal voltage of
Temperature Control
between TP2 & TP3
See Figure 1
DC 0 V
DC 12 to
32 V
Power Supply
Failure
Normal
Change
Power Supply
See Procedure B
Correct DC Voltage
Wrong
Compressor runs
YES
NO
Good
OK
(10.5 - 32 VDC)
Check Battery
Voltage
Check DC
Polarity
Wrong
Reverse Polarity
& Check operation
(Red+/Blk-)
Good