Owner's Manual

MTC-50
TROUBLE DIAGNOSIS
Revision: March 2005 2005 Altima
SYSTEM DESCRIPTION
Component Parts
Air mix door control system components are:
● Front air control
● Air mix door motor (LCU)
System Operation
The front air control receives signals from its various dials and switches. The front air control then sends air
mix door, mode door and intake door motor opening angle data to the air mix door motor LCU, mode door
motor LCU and intake door motor LCU.
The air mix door motor, mode door motor and intake door motor read their respective signals according to the
address signal. Opening angle indication signals received from the front air control and each of the motor posi-
tion sensors are compared by the LCUs in each motor with the existing decision and opening angles. Subse-
quently, HOT/COLD or DEFROST/VENT or FRESH/RECIRCULATION operation is selected. The new
selection data is returned to the front air control.
COMPONENT DESCRIPTION
Air Mix Door Motor
The air mix door motor is attached to the heater and cooling unit. It
rotates so that the air mix door is opened or closed to a position set
by the front air control. Motor rotation is then conveyed through a
shaft and the air mix door position is then fed back to the front air
control by PBR built-in air mix door motor.
DIAGNOSTIC PROCEDURE
SYMPTOM: Discharge air temperature does not change.
Perform diagnostic procedure for LAN system circuit. Refer to MTC-44, "
LAN System Circuit" .
WJIA0922E
WJIA0044E