On the air con pressure sensor plug, pin 1 and 3 give a 5V reference signal. Pin 3 is positive.

For the clutch to operate you need at least 1 volt between pins 1 and 2. Pin 2 is positive..

I don't know what pressure this represents.

Let me know where you measure your 1.25v.


You can emulate a working sensor and correct pressure by disconnecting pin 2 from sensor and placing a 470k ohm resistor between pin 3 and the pin2 lead to ecu.

This will eliminate a sensor or pressure fault.
 
andyfreelandy said:
Have you fitted and worked the air con clutch relay in the engine fuse box?? Does it operate?
Click to expand...
1.25 volts on pins 1 and 2. 5 volts on pins 1 and 3. 1 is a minus, or chassis. The clutch relay works fine, I can click it through Delphi or Thinkdiag.
 
Last edited:
Andrew-Dp said:
1.25 volts on pins 1 and 2, 5 volts on pins 1 and 3. 1 is a minus, or chassis. The clutch relay works fine, I can click it through Delphi or Thinkdiag.
Click to expand...
All these sensors go into the dashboard, I already installed the panel for a friend)) the result is the same.
 
Andrew-Dp said:
Hello. Or maybe the problem is that I turned off the Webasto diesel heater? The positive wire to the heater activation command is disconnected.
Click to expand...
The webasto is a stand alone heater, so has no connection to the AC system. It receives a simple on command when the ignition is turned on, then it's own EU fires the heater when needed.
 
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