Lennox G50UHi Unit Information page 34

B−INDOOR BLOWER CONTROL MODULE
D Ensure that 6−pin connector is securely plugged into blower control module.
D Ensure that 3−pin motor connector is securely connected.
D Check power supply wiring to blower control module from 120HOT and neutral
terminals on SureLight® control board.
D Ensure that leads from 6−pin connector are securely connected to the SureLight®
control board.
D Make sure blower access panel is replaced properly to close door interlock switch and
energize SureLight control board.
D Check for proper demand from thermostat.
D Ensure that 3−pin motor connector is securely connected.
D Connect lead from ACB Cool to 120HOT terminal.
D Make sure blower access panel is replaced properly to close door interlock switch and
energize SureLight® control board.
D Repeat with ACB Heat and ACB Low leads.
Does motor operate when
SureLight® control board?
D Disconnect 6−pin connector from blower control module. Also, disconnect 3−pin motor
connector.
D Disconnect wires from HOT and Neutral terminals on blower control module. Connect
these wires directly to the blower motor (may require splicing).
D Make sure blower access panel is replaced properly to close door interlock switch and
energize SureLight® control board.
Does motor operate when
power is applied to unit?
Blower control module is not working
properly.
module.
Indoor blower motor does not operate with
heating, cooling or continuous fan demand.
Is motor operating properly?
NO
CHECK SURELIGHT® OPERATION
power is applied to
NO
CHECK BLOWER MOTOR
YES
Replace blower control
PROBLEM
CHECK WIRING
YES
Recheck all wiring connections.
Problem is with SureLight® control board.
YES
ACB terminals are not energized. Follow
SureLight® diagnostic procedures.
Blower motor is not working properly.
NO
Follow motor diagnostic procedures
and replace blower motor, if necessary.
Page 34