Nissan Maxima Service and Repair Manual: Mode door control system

System Diagram

System Description

The mode door is automatically controlled by the temperature setting, ambient temperature, in-vehicle temperature, intake temperature and amount of sunload.

SYSTEM OPERATION

• The A/C auto amp. receives data from each of the sensors.
• The A/C auto amp. sends the air mix door, the mode door and the intake door opening angle data to the air mix door motor LCU(s), the mode door motor LCU and the intake door motor LCU.
• The air mix door motor(s), the mode door motor and the intake door motor read their respective signals according to the address signal. Opening angle indication signals received from the A/C auto amp. and each of the motor position sensors, are compared by the LCUs in each door motor with the existing decision and opening angles.
• Next, HOT/COLD, DEF/VENT or FRE/REC operation is selected. The newly selected data is returned to the A/C auto amp.

Door Motor Circuit

Mode Door Control Specification

Mode position can be selected manually by pressing the MODE switch or the DEF switch on the A/C switch assembly. Pressing the AUTO switch allows automatic control by the A/C auto amp. During the automatic control of a mode position, a mode door position (VENT, B/L, FOOT, or D/F) is selected based on a target air mix door opening angle and the sunload sensor, calculated by the A/C auto amp. In addition, the D/F is selected to prevent windshield fogging only when ambient temperature is extremely low.