K8 connector pin #1 white/red (W/R) to pin #2 light blue (LBU). If 24VAC is not present and 1A 24VAC fuse is good, replace the control transformer. If 24VAC is present and "POWER OK" LED is off, CB is bad and must be replaced.
IS Diagnosis: Check that IS green LED is on. If "POWER OK" LED is on and IS green LED is off, check 20VDC at CB K6 connector brown (BR) wire to dark blue (DBU) wire. If 20VDC is not present, confirm S1 dip switch 7 is in the "ON" position. If S1 dip switch 7 is in the "ON" position and 20VDC is not present, CB is bad and must be replaced. If IS yellow LED is on or flashing, move ice away from IS lens. If no ice is present, clean the lens with a warm, clean damp cloth. If yellow LED is still on or flashing after cleaning the lens, replace IS. MBC Diagnosis: Move S1 dip switch 7 to the "OFF" position. Check that the actuator paddle is properly positioned. Check for continuity across MBC proximity switch. When MBC proximity switch is closed 0VDC is read across
CB K8 connector pin #3 gray (GY)and #4 gray (GY). 5VDC is present between CB K8 connector pin #3 gray (GY) or #4 gray (GY) to CB white K5 connector pin closest to red K4 connector (5VDC gnd). If 5VDC is not present, CB is bad and must be replaced.
CB monitors the following switches with 5VDC: Control Switch, Gear Motor Protect Relay (relay terminals 3 & 5), Float Switch, and Mechanical Bin Control. When 5VDC is present across any of these switches, the switch is open.
6)Fill Cycle – "WTRIN" LED is on. WV energizes. The 90-second low water safety timer begins. LF/S closes. Nothing occurs at this time. The reservoir continues to fill until UF/S closes. The closing of the UF/S de-energizes WV, terminates the 90‑second low water safety timer, and starts the 30‑minute freeze timer. Diagnosis: Check that WV energizes and water fills the reservoir. If not, check for water supply line shut‑off valve closed, clogged water filters, and clogged WV screen. Next, check 24VAC to WV from CB K2 connector pin #8 white/brown (W/BR) wire to a light blue (LBU) neutral wire. Check for continuity through WV solenoid. If open, replace WV. If WV is energized and refill exceeds 90-second low water safety timer (fill timer) with no water in the reservoir, check for DV leaking. If reservoir is full and overflowing check for open UF/S. Check that WV shuts off when UF/S closes. If not, check UF/S continuity, red (R) wire to black (BK) wire. Clean or replace if necessary. See "IV.E. Float Switch Check and Cleaning."
Note: Low Water Safety–If UF/S remains open 90 seconds after WV energizes, a 1‑beep alarm sounds. This alarm resets automatically once UF/S closes.
7)Ice Purge Cycle – "GM" LED is on. WV de-energizes and "WTRIN" LED turns off.
30-second GM delay timer and 30‑minute freeze timer start. The 30‑second GM delay timer terminates, GMR (X2 on CB), GM, GMPR, and EH energize. 5-minute ice purge timer starts. Diagnosis: If "GM" LED is off, check that WV de‑energizes and UF/S closes. If "GM" LED is on and GM is off, confirm 115VAC at CB K1 connector pin #3 brown (BR) to white (W) neutral. Check for 115VAC at CB K1 connector pin #2 white/ black (W/BK) to a white (W) neutral. If no voltage is present, CB is bad and must be replaced. If 115VAC is present, check GM fuse, GM internal protector, GM windings and capacitor, and GM coupling between auger and GM.