Does the AC compressor have a pressure control valve?
 

I have a 2006 X5, 6-speed. It's new to me. The AC compressor won't make a pressure differential - it's not moving refrigerant. The clutch engages.

When the wife's Lexus did this, it was the easiest fix ever - a pressure control valve. One bolt and an electrical plug, that's all. But I don't think these cars have a control valve, do they? I saw a listing for one when I was looking for a compressor, but you see all sorts of crazy stuff on the internet...

The pressure switch is located on the right side frame rail A/C line. Unfortunately, to change it out, the system has to evacuated. If you unplug the switch, the aux fan should go to full speed.
A you sure the clutch is not slipping? Have you connected A/C hoses to check pressures?

My A/C compressor replacement.

If you have auto air (IHKA) then there is a non-electric VOLUME/displacement control valve built into the compressor that works on a pressure differential. It's replaceable but not easy to get or get to. Some have had success with revving the engine to unstick the valve but usually end up replacing the compressor. I don't think they used an electric valve in the E53.

There is definitely not an electric valve. It would have to be mechanical. If it's no easier than replacing the compressor, then I'll replace the compressor. Maybe, after I get this one out, I'll take a look and see if I can replace the valve with it on the bench. If I can get a valve in it and make it work again, it will be ready to go for when the Amazon compressor fails.

I'll keep the pressure sensor trick in mind. That makes sense as to why the fan isn't coming on - the compressor isn't building enough pressure to tell it to.

Vacuum, refrigerant recovery, etc... that's no problem. Been doing that for more than 30 years.

Thanks for the help!

There is definitely not an electric valve. It would have to be mechanical. If it's no easier than replacing the compressor, then I'll replace the compressor. Maybe, after I get this one out, I'll take a look and see if I can replace the valve with it on the bench. If I can get a valve in it and make it work again, it will be ready to go for when the Amazon compressor fails.

I'll keep the pressure sensor trick in mind. That makes sense as to why the fan isn't coming on - the compressor isn't building enough pressure to tell it to.

Vacuum, refrigerant recovery, etc... that's no problem. Been doing that for more than 30 years.

Thanks for the help!

Are you looking for the expansion valve? It's behind the passenger side center console panel.

https://www.youtube.com/watch?v=XLKx7-m5LUQ

Not the expansion valve. Some of the "fancier" cars started doing variable volume type stuff so that you would have the same ammount of pumping at idle as you do on the interstate. That way the AC doesn't warm up when you are at a stoplight. One of the ways was to set the compressor to overpump, then use a bypass valve to regulate the pressure.

Oh yeah variable compressors. Variable power steering with sensors. Variable valve timing with solenoids. More junk to troubleshoot for us home mechanics.

I found the pressure control valve. It's at the 6 o'clock position, at the back of the compressor. It's held in with a circlip and would be easy to change on the bench, but not in the car. I won't be changing one in this compressor. It's not the original compressor and it's pretty crunchy inside.

Yes you have a Calsonic CSV717 variable displacement compressor.

I wouldnt bother with the valve, many stories of replacements not lasting.

Mine would sometimes work and sometimes not, till it just didnt. Replaced the whole thing.

Good time to check the tensioner unit and tensioner/idler pulleys too.