A/C sytem on a '02 BMW 330i?

Question

Right at the dehumidifier (filter) there is a pressure sensor, right at the sensor there are 3 wires coming in, I know I can fool the sensor (if it were bad) by putting 2 wires together but which of the 3? Why is that in any other car I have seen there is only 2 wires at the sensor not 3 like this one? Can someone help me identify the 2 I'm looking for?

Snowie:
Thanks for your answer, and I also think that buying the sensor is the way to go, but I'm in Guatemala and BMW parts are not so easy to find and if you find them they are expensive, so I want to rule out the possibility of the sensor being fine and maybe the control unit being the problem, so what I need to know is which cables to jump? Thanks again

Answer 1

Ok, I think I understand what you are trying to say...

You mean near the RECEIVER/DRYER, there is a pressure sensor that activates the COMPRESSOR if sufficient R-134a is present in the system.

And for some reason, you suspect this sensor is faulty in your car and you want to override it by shorting the sensor instead of replacing it.

Here's the problem. The pressure sensor is there for a reason. This is a SAFETY DEVICE to protect the compressor and system. Shorting the wire to fool the system isn't the best or safe way to fix the problem.

Don't cheap out, buy a new sensor. Here's the part number: 64539141957

As far as I know, the pressure sensor not only senses low pressure, it also senses high pressure. If for some reason the pressure in your system gets too high, it will also stop the compressor so it won't explode.

All 3 pressure sensor wires goes straight into the heating & A/C control module. I only see a wiring diagram here, but nothing telling me which wires to short. You can risk it and try to use a volt meter to see which wire pair has a voltage difference, then close the contact to see what happens... I'm guessing one tells the system the pressure is too low, the other tells it the pressure is too high.