HVAC Control System Sensor Resistance Values

To assist with HVAC sensor diagnosis, please refer to the table below for sensor resistances. The values indicated may vary slightly from those shown due to changes in ambient temperature

SENSOR TEMPERATURE °C	FRONT EVAPORATOR TEMPERATURE SENSOR OHMS Ω	REAR EVAPORATOR TEMPERATURE SENSOR OHMS Ω	IN CAR TEMPERATURE SENSOR OHMS Ω	AMBIENT TEMPERATURE SENSOR OHMS Ω	LOW PRESSURE TEMPERATURE SENSOR OHMS Ω
0	4851	4851	27600	6318	32014
10	2959	2959	17970	3852	19691
20	1866	1866	11990	2418	12474
30	1214	1214	8184	1559	8080
40	811	811	5704	1031	5372
50	556	556	4053	697	3661

SENSOR TYPE	RESISTANCE VALUE	AMBIENT TEMPERATURE
Front Evaporator Temperature Sensor	1600 ohms	22°C
Rear Evaporator Temperature Sensor	1600 ohms	22°C
Duct Air Temperature Sensor	3000 ohms	22°C
In Car Temperature Sensor (measured at pins 3 and 5)	9000 ohms	22°C
Compressor Solenoid Sensor	10000 ohms	22°C
Compressor Clutch Sensor	4300 ohms	22°C

Air Conditioning system pressure table (Static)

NOTE:

The air conditioning system pressure values in the table below are expected when the vehicle is static with the air conditioning system switched off and with refrigerant in the system either partly or fully charged
The engine compartment and passenger compartment need to be at the same temperature as the workshop otherwise this will have an effect on the system pressure

AMBIENT TEMPERATURE °C	AIR CONDITIONING SYSTEM PRESSURE R134A (bar)	AIR CONDITIONING SYSTEM PRESSURE HFO1234YF (BAR)
0	2.93	3.16
5	3.50	3.73
10	4.15	4.38
15	4.88	5.10
20	5.72	5.92
25	6.65	6.83
30	7.70	7.84
35	8.87	8.95
40	10.16	10.18
45	11.60	11.54
50	13.18	13.02