Model Icb427R Refrigerator Membrane Switch Ribbon Cable Test - Wolf Sub-Zero ICB400 Series Service Manual

TroubleShoot Guide
MODEL ICB427R REFRIGERATOR MEMBRANE SWITCH / RIBBON CABLE TEST PROCEDURE
If the integrity of the refrigerator control panel assembly is suspect, continuity tests should be performed at the mem-
brane switch ribbon cable terminal housing. Begin by removing the control panel assembly from the unit and place it
on a solid surface. Disconnect the ribbon cable from control panel PC board.
How To Identify Pin 1 on Terminal Housing
The ribbon cable wires are exposed at the back of the terminal housing, but since there are two vendors of the
membrane switch, determining the location of pin 1 is not always easy. To identify the pins, follow these guidelines:
1. If terminal housing is BLUE, then pin 1 is closest to arrow on housing.
2. If terminal housing is BLACK, check for continuity between first and third pins at each end of housing while
pushing refrigerator WARMER key. If there is continuity, then pin 1 is at that end.
ICB427R Refrigerator Membrane Switch/Ribbon Cable Test Procedure
1. Press no keys on membrane switch. Check for continuity between all pin combinations. With no keys pressed,
there should be no continuity between any pins.
2. Press POWER key, there should be continuity across pins 3 & 4.
3. Press ALARM key, there should be continuity across pins 2 & 4.
4. Press WARMER key, there should be continuity across pins 4 & 5.
5. Press COLDER key, there should be continuity across pins 1 & 3.
NOTE: If any of the tests show failure, replace entire control panel assembly.
Membrane Switch in
Control Panel Assembly
Figure 7-2. Refrigerator Control Panel Assembly with Cut-Away View to Show Ribbon Cable
7011544 - Revision A - November, 2008
International W ine Storage
International W ine Storage
Terminal Housing
NOTE: See "How To Identify Pin 1", above.
7-20
Series
Series
(ICB400)
(ICB400)
Ribbon Cable