All values measured to ground unless otherwise noted
Conn./Plug/Pin	Pin Information	Test Value	Comments
N22
1.1	"Diagnostic port" for readout and diagnostic purpose.	No reliable test. Check continuity to X11/4 pin 16.	Note 1
	Stored DTC data's are memory persistent
1.2	In-car temperature signal input, controls aspirator blower.	NTC. Decreasing resistance with increasing temperature. Approx. 20 kOhms at 10 °C, approx. 4.5 kOhms at 45 °C.	Note 1
1.3	Heater core signal input, left side.	NTC. Decreasing resistance with increasing temperature. Approx. 20 kOhms at 10 °C, approx. 4.5 kOhms at 45 °C.	Note 1
1.4	Pin not used
1.5	Evaporator temperature signal input.	NTC. Decreasing resistance with increasing temperature. Approx. 9 kOhms at 0 °C, approx. 1.2 kOhms at 45 °C.	Note 1
1.6	ECT signal input.	NTC. Decreasing resistance with increasing temperature. Approx. 6.5 kOhms at 20 °C, approx. 200 Ohms at 120 °C.	Note 1
1.7	Voltage output, supplies refrigerant pressure sensor.	Ignition on, 5 VDC.	Leads to B12 via
1.8	Refrigerant pressure sensor signal input, used to protect A/C compressor when pressure drops.	Approx. 0-5 VDC depending on actual pressure value.	Feed from B12 pin 2
1.9	Sensors common ground, in A/C system.	Approx. 12 VDC to pin 2.8.	Feed from Z6/16
1.10	Serial port II, transmits data Tx - refrigerant pressure - rpm increase to Instrument Cluster (IC). Tx signals are linked on CAN-Bus inside of IC and sent to other ECM.	No reliable test. Approx. 5 VAC when data transmission active.	Note 1
1.11	Circuit 15x, power input.	Ignition on, 12 VDC.	Feed from F1f18
1.12-16	Pins not used
1.17	VSS signal input	Ignition on, lift front of vehicle. Turn left front wheel > 1 rev/sec by hand > 3 VAC or with vehicle moving
1.18-24	Pins not used
1.25	Pin not used
1.26,27	Pins not used
2.1	Signal output, blower speed control.	Ignition on. > 0.7 VDC with blower set to "min". > 5.0 VDC with blower set to "max".
2.2,3	Pins not used
2.4 2.5	Recirculated air flap switchover valve Valve (short stroke) Valve (long stroke)	Ignition on. < 1V < 1V
2.6	Blend air flap valve	Ignition ON Switch on Display "LO" 11-14V Measure across pins 2.6 and 2.18
2.7	Pin not used
2.8	Circuit 30, main power input.	12 VDC all times.	Feed from F1f12
2.9	Circuit 15, power input.	Ignition on, 12 VDC.	Feed from F1f2 via Z3/11
2.10	RPM increase signal output. Idle speed increases with A/C compressor on.	Engine running. 12 VDC with A/C compressor on (defrost mode), 0 VDC with A/C compressor off (defrost "off").
2.11-12	Pins not used
2.13 2.14	Footwell flap switchover valve Valve (short stroke) Valve (long stroke)	Ignition on. 11-14V 11-14V
2.15	Diverter flap valve	Ignition ON Switch on Display "HI" <1V Measure across pins 2.15 and 2.18
2.16	Auxiliary fan relay stage 2 activation signal output	Ignition on, set air volume selector to max < 1 VDC L/R fans running at high speed
2.17	Circuit 58d input, "Dimmed Instrument Illumination" voltage.	Varies up to 12 VDC, depending on setting of dimming value or ambient brightness.	Short protected, current decoupled from circ. 58k
2.18	Switchover valve unit power supply output	Ignition on, 12 VDC
2.19	Main ground to W1.	Approx. 0 Ohms to ground.
2.20	Switched ground signal output, activates circulation pump.	Ignition off. Approx. 2-4 Ohms between pin 2.20 and 2.18. Check motor. Pump runs when grounded (Ignition on)
2.21	Duovalve output	Ignition ON Switch on Display "HI" 11-14V Switch on Display "LO" <1V
2.22 2.23	Defroster nozzle flap switchover valve Valve (short stroke) Valve (long stroke)	Ignition on. < 1V < 1V
2.24	Pin not used
2.25	Voltage output, activates A/C compressor.	A/C system on: Defrost on, EC off. 12 VDC with A/C compressor on. 0 VDC with A/C compressor off.
2.26-29	Pins not used.
Note 1	Refer to D. M. Climate Control Vol. 1, 3.2