Service Manual

35
B. Control Module Check
Before replacing a control module that does not show a visible defect and that you
suspect is bad, always conduct the following check procedure. This procedure will help
you verify your diagnosis. Always choose a neutral (W wire) to establish a good neutral
connection when checking high voltages. Also, conrm that there is a good neutral
connection to the control module terminal N5.
Alarm Reset: To silence the alarm, press and release the upper or lower button with
power on. For alarm information, see "II.D.2. Alarm Safeties."
Startup/Cool Down:
1) Check all wiring connections. Conrm that the DM cable, CTh, and DTh are properly
connected.
2) Move the power switch to the "ON" position.
3) Check for 115VAC between CM terminals L3 and N5. If 115VAC is not present, check
power supply and power switch.
4) Check that DM is on and cabinet temperature is displayed. If not, replace DM and CM.
5) Freezer: Check that EvapFM is energized. Make sure that the door(s) are closed and
the door switch is engaged. Next, check for 115VAC between CM terminals F6 and N5.
If 115VAC is not present, replace CM.
6) Check that Comp and ConFM energize. If not, check for 115VAC between CM terminals
C1 and N5. If 115VAC is not present, replace CM.
Defrost:
7) Press and hold the lower button until "dEF" appears on DM.
8) Conrm that the Comp, ConFM, and EvapFM (freezer) de-energize. Check for 115VAC
between CM terminals C1 and N5 for Comp and ConFM, then between terminals F6
and N5 (freezer) for EvapFM. If "dEF" is displayed and there is 115VAC between the
terminals, replace CM.
9) Freezer: Conrm that DH energizes. Check for 115VAC between CM terminals H4 and
N5. If "dEF" is displayed and 115VAC is not present, replace CM.
10) Check that the components restart after defrost termination.
Refrigerator: Comp and ConFM energize as soon as the DTh termination temperature
is satised. See "Defrost Termination" under "IV.A.1.9) Defrost" and "IV.C. Thermistor
Check." If components fail to start, replace CM.
Freezer: Comp and ConFM energize 3-minutes after defrost termination temperature
is satised. EvapFM energizes 5-minutes after that (except manual defrost), and the
cabinet temperature appears on DM 5-minutes after EvapFM energizes. See "Defrost
Termination" under "IV.A.2.9) Defrost" and "IV.C. Thermistor Check." If components fail
to start, replace CM.
Legend: CM–control module; Comp–compressor; ConFM–condenser fan motor;
CTh–cabinet thermistor; DH–defrost heater; DM–display module;
DTh–defrost thermistor; EvapFM–evaporator fan motors;