Troubleshooting - Procedure A - Norcold DC0040 Service Manual

Troubleshooting – Procedure A
Thermostat "ON" Compressor Does Not Run
Is Temperature
Control LED on?
NO
Check Supply
Voltage
(10.5 – 32V DC)
(85 – 132V AC)
CORRECT
Power
Source
AC
Measure Terminal
Voltage of Temperature
Control Between TP2 &
TP3. (See Figure 1)
Note: Measurements taken with 12.8V DC or 120V AC power supply.
Red
Brown
TP3
TP1
Figure 1 – Temperature Control
Measure Terminal
Voltage Of Temperature
YES Control Between TP1 &
TP2. (See Figure 1)
Correct
Voltage
INCORRECT
Check Both Check DC
DC Fuses BLOWN Polarity
DC
OK
Replace
10A Fuse
(See Figure 2)
DC
OPERATION
AC
DC 0V
OPERATION
DC 12
Normal
to 32V
Black
TP2
DC
OPERATION
Check AC
Power Supply
AC
DC 0V
(37 – 45V DC)
OPERATION
(See Figure 5)
DC 2V Normal
DC Power
DC 5V
Supply Failure
Compressor
OK
Runs
YES
NO
Reverse Polarity
& Check Operation
INCORRECT
(Red + / Black -)
OK
Compressor
Runs
NO
Check AC
Power Supply
(37 – 45V DC)
(See Figure 5)
See
Procedure B
Figure 2 – Fuse Locations
Note: If 10 Amp fuse is blown,
check wiring of vehicle.
Short Circuit
Short Circuit
GOOD
BAD
See
Procedure B
Change DC
Power Supply
Replace
Compressor
10A Fuse
Runs
(See Figure 2)
NO
OK
YES
DC Power
Supply Failure
DC Power
Supply Failure
GOOD
BAD
3
Change DC
Power Supply
Change DC
Power Supply
Change AC
Power Supply
OK
YES
Change DC
Power Supply
Change DC
Power Supply
Change AC
Power Supply