Service Guide

18
Defrost Diagnosis:
1a) Time-Initiation: 2-hr. defrost timer terminates.
(1) CM Diagnosis: Conrm defrost icon turns on, "dEF" is displayed, and Comp
icon turns off. If not, replaceCM.
(2) Comp and ConFM Diagnosis: Conrm Comp and ConFM de-energize.
If not, check for 115VAC at CM C1 (R or V) to neutral (W). If 115VAC is present,
replace CM. If 115VAC is not present and Comp and ConFM continue, check
CR#6(R) to neutral (W). If 115VAC is present, replace CR.
1b) Manual-Initiation: After pressing the manual defrost button, check the following:
(1) CM Diagnosis: Conrm Comp icon turns off, defrost icon turns on, and "dEF" is
displayed. If not, replace CM.
(2) Comp and ConFM Diagnosis: Conrm Comp and ConFM de-energize.
If not, check for 115VAC at CM C1 (R or V) to neutral (W). If 115VAC is present,
replace CM. If 115VAC is not present and Comp and ConFM continue, check
CR#6(R) to neutral (W). If 115VAC is present, replace CR.
2) Defrost Temperature Termination: DTh warms to 40°F (4.4°C). If not, conrm
DTh status. See "II.D. Thermistor Check." If DTh is in proper range, have Comp and
ConFM energized? If not, see "7d) Comp and ConFM Diagnosis"above.
Legend: CL–cabinet light; CLS–cabinet light switch (FGY); CM–control module;
Comp–compressor; ConFM–condenser fan motor; CR–compressor relay;
CTh–cabinet thermistor; DS–door switch (FS/HS); DSR–door switch relay
(FS/HS); DTh–defrost thermistor; EvapFM–evaporator fan motors;
HPS–high-pressure switch; TXV–thermostatic expansion valve