Climate Control Unit Inputs and Outputs

Fig 1: Identifying Climate Control Unit 40P Connector

Courtesy of AMERICAN HONDA MOTOR CO., INC.

CAVITY AND WIRE COLOR DESCRIPTION

Cavity	Wire color	Terminal name	Description	Signal
1	LT BLU	Illumination (+)	Input voltage for illumination	With headlight switch ON: battery voltage
3	WHT	Variable Capacity Control Solenoid Valve In	Ground for variable capacity control solenoid valve	Less than 0.5 V at all times
4	GRN	Variable Capacity Control Solenoid Valve Out	Outputs 12 V to variable capacity control solenoid valve	Variable voltage based on cooling load. Battery voltage with compressor at maximum
5	GRY	Control Motor Relay	Switches control motor relay	With control motor relay OFF: battery voltage With control motor relay switched ON: Less than 0.5 V
6	PUR	Navigation Unit (SO)	Communication signal from navigation	With ignition switch ON (II): pulses (about 2.5 V)
7	ORN	Navigation Unit (SI)	Communication signal from navigation	With ignition switch ON (II): pulses (about 2.5 V)
8	BRN	Navigation Unit (CLK)	Communication signal from navigation	With ignition switch ON (II): pulses (about 2.5 V)
9	BLU	Blower Feedback	Feedback signal from blower power resistor	With ignition switch ON (II) and blower ON: between 5 V and 12 V. Voltage decreases as blower speed increases
10	RED	Blower Transistor Control	Outputs blower power resistor gate voltage	With ignition switch ON (II) and blower OFF: 0 V. Voltage increases as blower speed increases
12	GRY	A/C Pressure Sensor 5	V Outputs 5 V to pressure sensor	With climate control unit ON: about 5.0 V
14	LT GRN	A/C Pressure Sensor	Detects A/C pressure sensor signal	With climate control unit ON: about 0.4-4.6 V, depending upon refrigerant pressure
15	LT BLU	In-car Temperature Sensor	Detects in-car temperature sensor signal	With ignition switch ON (II): about 1.0-4.0 V (depending on in-car temperature).
16	PNK	Outside Air Temperature Sensor	Detects outside air temperature sensor signal	With ignition switch ON (II): about 1.0-4.0 V (depending on outside air temperature).
17	BRN	Evaporator Temperature Sensor	Detects evaporator temperature sensor signal	With ignition switch ON (II): about 1.0-4.0 V (depending on evaporator temperature).
18	PUR	Sunlight Sensor	Detects sunlight sensor signal	With ignition switch ON (II) and sensor out of direct sunlight: 3.6 V or more With ignition switch ON (II) and sensor in direct sunlight: 3.5 V or less
20	YEL	IG2	IG2 Power supply	With ignition switch ON (II): battery voltage
21	GRN	Illumination (-)	Detects illumination control signal	With headlight switch ON: voltage varies as dash lights brightness varies
23	LT GRN	M-COM	Communication signal from climate control motors	With ignition switch ON (II): pulses (about 2.5 V)
24	LT GRN	B-CAN	B-CAN communication signal	With ignition switch ON (II): pulses (about 2.5 V)
29	YEL	Audio Unit (SO)	Communication signal from audio unit	With ignition switch ON (II): pulses (about 2.5 V)
30	RED	Audio Unit (Clock)	Communication signal from audio unit	With ignition switch ON (II): pulses (about 2.5 V)
31	BLK	Ground for climate control unit (G503)	Ground for control unit	Less than 0.2 V at all times
32	PNK	Control motor ground	Common ground for climate control motors	Less than 0.2 V at all times
33	ORN	Sensor ground	Common ground for sensors	Less than 0.2 V at all times
36	WHT	Driver's Air Vent Temperature Sensor	Detects driver's air vent temperature sensor signal	With ignition switch ON (II): about 1.0-4.0 V (depending driver's air vent temperature).
37	LT BLU	Passenger's Air Vent Temperature Sensor	Detects passenger's air vent temperature sensor signal	With ignition switch ON (II): about 1.0-4.0 V (depending passenger's air vent temperature).
39	PUR	Control Motor Relay	Inputs 12 V from control motor relay	With control motor relay OFF: about 0 V With control motor relay ON: battery voltage
40	GRN	Control Motor Power	Outputs 12 V to climate control motors	With control motor relay OFF: about 0 V With control motor relay ON: battery voltage