Service Manual

26
4) 5VDC Output Checks:
CB K9 Connector: Control Switch (CB K9 #1 and #2) (open contacts for icemaking,
closed contacts for drain), High-Pressure Switch (CB K9 #3 and #4), Compressor
Control Relay/Gear Motor Protect Relay (K9 #5 and #6).
CB K8 Connector: Bin Control (2) (K8 #3 and #4) and Float Switch (K8 #5 (common),
#6 (lower), and #7 (upper)).
When checking 5VDC control voltage, always place the red positive test lead from
the multimeter to the CB white K5 pin closest to the CB red K4 connector. See Fig. 2.
Then place the black negative test lead from the multimeter to the corresponding pin to
complete the 5VDC check.
Red positive test lead
to K5 pin closest to K4
connector
Fig. 2
Control Board K9 Connector
Red Positive
Test Lead
Black Negative
Test Lead
Multimeter
5VDC
Control Switch
white/black (W/BK)
High-Pressure Switch
yellow (Y) wires
Compressor Control Relay/
Gear Motor Protect Relay
(terminals #3 and #5)
white/orange (W/O)
a) Control Switch – CB K9 #1 (W/BK) and CB K9 #2 (W/BK):
5VDC is present between CB white K5 connector, pin closest to CB red
K4 connector and CB K9 #1 (W/BK) at all times. If 5VDC is not present, replace
CB. When the control switch is in the "ICE" position, the control switch contacts
are open. 0VDC is present between CB white K5 connector, pin closest to CB red
K4 connector and CB K9 #2 (W/BK). When in the "ICE" position, 5VDC is present
between CB K9 #1 (W/BK) to CB K9 #2 (W/BK). When the control switch is in the
"DRAIN" position, the control switch contacts are closed. 5VDC is present between
CB white K5 connector, pin closest to CB red K4 connector, to CB K9 #1 (W/BK)
or#2(W/BK). If 5VDC is not present, replace CB. 0VDC is present from CB K9
#1(W/BK) to CB K9 #2 (W/BK).
b) High-Pressure Switch – CB K9 #3 (Y) and CB K9 #4 (Y):
5VDC is present between CB K5 connector, pin closest to CB red K4 connector and
CB K9 #3 (Y) at all times. When the high-pressure switch is closed, 5VDC is present
between CB K5 pin closest to CB K4 connector to CB K9 #3 (Y) and CB K9 #4 (Y).
If 5VDC is not present, replace CB. When the high-pressure switch is closed, 0VDC
is present at CB K9 #3 (Y) to CB K9 #4 (Y). When the high-pressure switch is open,
5VDC is present at CB K9 #3 (Y) to CB K9 #4 (Y). If the high-pressure switch is open
and CB is not in alarm, replace CB. If5VDC is present at CB K9 #3 (Y) and not at
CB K9 #4 (Y), the high-pressure switch is open and CB sounds a 3-beep alarm.
Check continuity across the high-pressure switch (CB K9 #3 (Y) and CB K9 #4 (Y)).