Aircon not working

[malcthom]

AC ceased working abruptly on 2003 E53 3.0d! Not good when 36C outside!!
Relevant fuses are intact.
Compressor will not kick in when AC selected at head unit. It will rotate easily by hand so not seized. Also aux fan will not run. Have checked and have power to aux fan. Have not checked low & high side pressures of system as yet.
Just wondering whether a faulty automatic aircon sensor unit (part #64116917001) that sits on the main fan shroud, would shut down both the aux fan and compressor? Also will the compressor run if aux fan not working? Have read ALL the forums re this and no consensus of opinion.
Are there any relays controlling the two also?

[Isambard]

I don't know enough about aircon, but I know 100% the compressor and indeed the whole system WILL work without the aux fan. I know this because my aux fan is knackered but I still have aircon..

[malcthom]

Am I right in assuming the final stage resistor just controls the blower so should not be affecting the compressor or aux fan?

[Isambard]

Here, I found these for you..

http://www.xoutpost.com/bmw-sav-foru...-con-help.html

http://www.xoutpost.com/bmw-sav-foru...con-vents.html

http://www.xoutpost.com/bmw-sav-foru...n-problem.html

I don't know if they will help at all, but worth a look anyway.. Also, can you bypass the sensor and get 12v onto the compressor? That will at least elliminate the compressor and prove the sensor is bad or that there is no juice getting to the sensor

And if it IS the FSR here is the replacement guide:

http://www.xoutpost.com/articles/x5/...placement.html

Let us know how you get on

[malcthom]

Thanks Isambard.
Will get pressure chk done first then look at electrics.
Cheers

[bastereo]

That sensor box thing on the top of the fan shroud is for the automatic recirculation. Ac should still work without it. My ac system has a fault code for that sensor, auc sensor.

Most ac problems are caused by loss of refrigerant, the system has pressure sensors that will stop the ac from trying to run when there is not enough pressure, it does that to prevent damage to the compressor.
Check for leaks. They will look like just slightly oily spots on the compressor, lines, evaporator, drier, sensors, something will have just a slight oil residue. They can be very difficult to track down.
That is why ac leak tracer dye is so useful.

Sent from my SGH-i917 using Board Express

[malcthom]

Thanks bastereo
Am half hoping it has leaky seals or something and compressor is ok. Pressure test will tell. Will have to wait a few weeks til I get back from Thailand!
Does anyone know what the voltage to the compressor should be? Mine measures a steady 4.8V with or without the AC selected.
Also found the aux fan runs when the ac inline low pressure switch (?) is disconnected, compressor however does not kick in - maybe favours lack of refrigerant also.

[Isambard]

Sounds promising on the 'lack of refrigerant' theme..

[malcthom]

Quick update.
Unfortunately looks like it is the compressor ($1200 here in Australia) as when jump 12V directly to it is dead as a dodo!

[malcthom]

Also does anyone know whether the compressor on the diesel models differs from that on the gasoline vehicles? Schematic looks the same but different part no. on RealOEM.