The document provides information on diagnosing various connectors (J1-J12) for a GE refrigerator. It includes: - J1 connects to thermistors that monitor refrigerator temperatures and a model select. Issues can be faulty thermistors or main board. - J2 connects fan motors. Issues may be a burnt resistor or wiring short. Motors can be tested with a battery. - J3 connects a damper motor and encoder. Pins 1-4 carry voltage to the damper motor and pins 5-10 connect to the encoder.

1. GE Electronic Refrigeration Diagnostics J1 Connector Page 2-4 J2 Connector Page 5,6 J3 Connector Page 7 BPO encoder diagnostics J4 Connector Page 8 J5 Connector Page 9 J7 Connector Page 10 J8, J9, J11 and J12 Connections Page 11 defrost operation page 12 Inverter compressor page 13 Training and Technical Support Team 15-9-07

2. J1 Connector Thermistor and Model Select Connector (Overview) Pin 1 through 5 are the thermistor connections. Pin 5 is the common lead for the thermistors. The refrigerator thermistors have a negative temperature coefficient. As the temperature inside the refrigerator becomes colder, the resistance values of the thermistor increases. The encoder board or temperature setting interface sends a signal to the main board stating the temperatures the consumer has selected.The processor on the main board converts the selected temperatures to resistance values.The main board then monitors the thermistor’s resistance values. Based on these resistance values, the processor on the main board determines what actions it has to perfprm. Measure thermistor resistance with the wires disconnected from the board. Measure voltages with the wires connected to the board. Compare the resistance found to the temperature-resistance chart. (page 4) If the refrigerator is not defrosting, measure the resistance of the evaporator thermistor before defrosting the refrigerator. An evaporator thermistor that is out of calibration can prevent the main board from turning the defrost heaters on. To initiate a defrost cycle the main control board must read at least 30 to 40 K Ohms from the defrost thermistor located on the evaporator. Main control board will terminate the defrost cycle when thermistor read a temperature of at least 60°F or 7K Ohms. Pin 6 thru 9 are the model select connections.

3. J1 Connector Thermistors Pin 2 «FF2» Thermistor. Not used on all models. Measure the thermistor resistance by reading between the wire connected to this Pin and the wire connected tp Pin 5. Measure this thermistor voltage by reading between Pin 2 and Pin 5 Voltage should be between 2.8 and 3.5 V DC with a good thermistor. Pin 1 «FF1» Thermistor. Not used on all models. If used, measure thermistor resistance by reading the wire connected to this pin and the wire connected to Pin 5. Measure this thermistor voltage by reading between Pin 1 and Pin 5. Voltage should be between 2.8 and 3.5 V DC with a good thermistor. Pin 3 «FZ» Thermistor. Based on the resistance of this thermistor, the processor on the main board determines when to turn the compressor on or off. Measure thermistor resistance by reading between the wire connected to this pin and the wire connected to Pin 5. Measure this thermistor voltage by reading between Pim 3 and Pin 5. Voltage should be between 2.8 and 3.5 V DC with a good thermistor. Pin 4 Evaporator Thermistor based on resistance of this thermistor, the processor on the main board determines if the heater will come on for defrost and when to terminate defrost Measure thermistor resistance by reading between the wire connected to this Pin and the wire connected to Pin 5. Measure this thermistor voltage by reading between Pin 4 and Pin 5. Voltage should be between 2.8 and 3.5 V DC with a good thermistor. Pin 5. Common connection for thermistors and model select. (+5 V DC) Measure supply voltage for thermistors by reading between this Pin and Pin 3 on connector J4.

4. Thermistor Values 166.8 K -40 120.5 K -31 12.7 K 41 16.3 K 32 21 K 23 27.6 K 14 36.4 K 5 48.4 K -4 65 K -13 88 K -22 Resistance in k ohms Temperature in Degrees F 10 K 50 7.8 K 59 1.2 K 140 1.5 K 131 1.8 K 122 2.2 K 113 2.6 K 104 3.2 K 95 4 K 88 5 K 77 6.2 K 68 Resistance in k ohms Temperature in degrees F

5. J2 Connector Fan Motor Connections The J2 connector is for all of the fan motors. Some pins might not have a wire connected to them depending upon model features. If evaporator fan is not operating, check the resistor located by this connector. If it is burnt, replace the evaporator fan motor and the main board. If you measure no voltage at this connector, disconnect wiring and recheck voltages. If you now measure the correct voltage, check condenser fan and wiring to condenser fan for short to ground . To physically test fan motors, you may use a 9 volt DC battery. Connect white wire to the negative terminal, jump red and yellow together and connect to postive terminal. A good motor will run slowly.

6. J2 Connector Fan Motor Connections Pin 1. Evaporator Fan Tachometer provides feed back from fan motor. This feedback tells the processor what speed the fan motor is running. Check for voltage between Pin 1 and Pin 3. The voltage should be 6.3 V DC. Pin 2. Personality input to the board on some models with a FF fan motor. Pin 3. Common lead to all fan motors. Pin 3 to Pin 8, 13.7 V DC. Pin 4. Evaporator Fan. Pin 4 to Pin 3. Between 4 V DC and 12.4 V DC, +/- 10 %, depending on fan speed. Pin 5. Condenser Fan. Pin 5 to Pin 3. Between 4 V DC and 12.4 V DC, +/- 10 %, depending on fan speed on inverter models, 12.4V DC on non-inverter models. Pin 6. Fresh Food Fan (when used) Pin 6 to Pin 3. Between 4 V DC and 12.4 V DC, +/- 10 %, depending on fan speed. Pin 7. Quick Chill MC Fan (when used). Pin 7 to Pin 3. 13.7 V DC, +/- 10%. Pin 8. Fan power supply. +13.7 V DC. Pin 3 to Pin 8. To test Evaporator fan motor look for 12 volts between pin 3 and pin 8 AND 4,8,or 12 volts between pin 3 and pin 4. To test Condenser fan motor look for 12 volts between pin 3 and pin 8 AND 8or 12 volts between pin 3 and pin 5.

7. J3 Connector Damper motor and Encoder Connections Pins 1 thru 4 are the damper stepper motor connections. Pins 5 thru 10 are the Encoder board connection. J3 Pin 1 to J4 Pin 3, 6 V DC Traveling Voltage or 2.3 V DC standing voltage. J3 Pin 2 to J4 Pin 3, 6 V DC Traveling Voltage or 2.3 VDC standing voltage. J3 Pin 3 to J4 Pin 3, 6 V DC Traveling Voltage or 2.3 V DC standing voltage. J3 Pin 4 to J4 Pin 3, 6 V DC Traveling voltage or 2.3 V DC standing voltage. J3 Pin 10. Double Function Pin Encoder Connection Not on all models or on inverter compressor models used to transmit speed data to compressor inverter module on some models. 1.5 to 3 V DC measured between J3 Pin 10 and J4 Pin 3. J3 Pin 5. Encoder Connection. Not used on all models. J3 Pin 6. Encoder Connection. Not used on all models. J3 Pin 7. Encoder Connection. Not used on all models. J3 Pin 8. Encoder Connection. Not used on all models. J3 Pin 9. Encoder Connection . Not used on all models. See Encoder table on how to diagnose the encoder.

8. J4 Connector FF,FZ, Dispenser, and Quick Chill Drawer Serial Data Communications Connections Pin 2 Dispenser Board, FF,FZ, And Quick Chill Drawer +13V DC Power supply. Pin 1 Dispenser, FF, FZ, And Quick Chill Drawer Data Communications on some models. Pin 4 Dispenser Board Input 1. (Input from the Dispenser Board on some models) Pin 3 Board DC Common Ground. Pin 5 Dispenser Board Input 2 (Input from the Dispenser Board on some models) Some pins might not have a wire connected to them depending upon model features.

9. J5 Connector Quick Chill Drawer Connections – Not used on all models Pin 1. Chiller Drawer Damper Motor Connection 13.7 V DC Pin 1to Pin 2. Pin 2. Chiller Drawer Damper Motor Connection 13.7 V DC Pin 1 to Pin 2. Pin 3. Chiller Drawer Damper Motor Connection 13.7 V DC Pin 3 to Pin 4 Not used on all models. Pin 4. Chiller Drawer Damper Motor Connection 13.7 V DC Pin 3 to Pin 4 Not used on all models. Pin 5. Chiller Drawer Thermistoer Connection. Measure resistance by reading between wires connected tp Pin 5 and Pin 6. Measure voltage by reading between Pin 5 and J 4 Pin 3 Voltage should be 5V DC. Pin 6. Chiller Drawer Thermistor Connection. Measure resistance by reading between wires connected to Pin 5 and Pin 6. Measure voltage by reading between J4 Pin 3 and Pin 6. Voltage should be between 2.8 and 3.5 V DC with a good thermistor. Measure thermistor resistance with the wires disconnected from the board. Measure voltages with the wires connected to the board

10. J7 Connector 120 V AC Outputs and Inputs Pin 9. Neutral Connection to Main Board. Pin 8. Blank. Pin 7. Input FZ Door 120V AC With door open between Pin 7 and Pin 9. Pin 6. Input FF Door 120V CA With the door open between Pin 6 and Pin 9. Pin 5. Output Quick Chill Heater 120V CA measured between Pin 5 and Pin 9. Pin 4. Input for auger from FZ door interlock switch. 120V AC between Pin 4 and Pin 9 with the FZ door closed. Pin 3. Output to dispenser water valve solenoid. 120V AC between Pin 3 and Pin 9 with the FZ Door closed and cradle depressed. Pin 2. Output to cube solenoid with Fz Door closed, cubes selected, and cradle switch depressed, 120V AC between Pin 2 and Pin 9. Pin 1. Output to auger motor. 120V AC between Pin 1 and Pin 9. FZ Door closed, cubes or crushed selected, and switch depressed. J7

11. J8, J9, J11 and J12 Connections 120 VAC input and output connections J8 Output to compressor 120 VAC measured between J8 and J7, Pin 9. J8 J9 Output to Defrost Circuit 120 VAC mesured between J9 and J7, Pin 9. J9 J11 Line in to Board. 120 VAC measured between J11 and J7, Pin 9. J11 J12 Output to Monogram drain pan heater 120 VAC measured between J12 et J7 Pin 9. The pan heater is on only during defrost. J12 J8 J9 J11 J12

12. Diagnosing Defrost Operation Verify that you have a full frost pattern and a No Defrost condition Remove main board cover from rear of unit With unit unplugged, use an ohmmeter to check resistance between Defrost pin on J9 and neutral wire on J7 connector. A good circuit should read aprx 27 ohms. (Alternately, you may use a flat blade screw driver to short between defrost pin and line pin at the J9 connector- looking for amperage draw) If resistance is good or heater draws amperage, check the evaporator thermisitor ( this is the device that terminates defrost) on the J1 connector between pin 4 and pin 5. ( do this test with the connector removed from the board, measuring at the connector) Compare resistance found to the resistance/temperature chart on page 4. Resistance should be greater than 36,000 ohms. If good, change the main board. Defrost Line Neutral

13. Inverter compressor diagnosis WARNING: When the refrigerator is plugged in, 120 VAC is always present at the inverter. The compressor leads must be connected to measure voltage output. If the compressor wires are not connected, or if an open occurs in one of the 3 lead wires or in the compressor, the inverter will stop voltage output. When checking inverter voltage output, connect the test-meter leads to any 2 of the 3 compressor lead wires at the inverter plug (plug should be connected). The same reading should be measured between any 2 of the 3 wires. When measuring signal voltage (from the main control board J15) at the inverter, a reading of 4-6 VDC will be measured with all wires connected. If the inverter wiring is disconnected, the board output will measure between 10-12 VDC. To test, measure 120 VAC into inverter and 4-6 VDC at J15 J15 connector 4-6 vdc output to inverter