AC not working 04 3.0

[Stevo96]

Someone else suggested the electromagnet? Is it easier just to replace the whole compressor? The car has done 210000k’s, approx 130000miles

[Stevo96]

I’m having a look on eBay for compressors, it looks like it changes from 2000-2003 then 2004 to 2007. I’m assuming they are different? And I guess the 4L one doesn’t fit either?

[andrewwynn]

Use realoem.com to determine the exact compressor model from your VIN. Search YouTube about how to fix just the clutch. The problem is the fix is usually for the clutch plate not the magent butt I'm sure it's been done.

[wpoll]

Applying power directly to the A/C clutch can work to test the clutch and compressor but you need to be careful doing this as it will bypass the over-pressure cut-out circuits - which can be bad. DAMHIK...

Fortunately, most compressors have an over-pressure valve built into them...

As for the fault in this case, it'll take some more diagnostics to pin it down. As usual, reading the fault codes with the correct tool might be a good next step.

[upallnight]

Originally Posted by Stevo96

Why do you say that? He’s a fully qualified auto electrician, do you know what the fault may be??

No,I don't know what the fault might be because I am not able to inspect the car or perform any type of test on the symptom, but the following quote by another X5 owner leads me to think he doesn't know that much as to how the ac system in a X5 operates.

Originally Posted by andrewwynn

Auc won’t disable AC. My wife’s AUC sensor was unplugged for about a year before I realized I forgot to plug it in.

Feeding the AC clutch direct power (or using the likes of foxwell scanner to manually engage the AC will activate the compressor no matter what if the clutch is functional.

If you in fact applied power to the clutch and nothing happened the clutch is broken.

The clutch can be rebuilt on many AC compressors and if it can be removed from the compressor while in the car you may circumvent vacuum and fill of the whole system that is needed if you replace the whole AC unit.

Could be the air gap between the pulley and the magnetic coil has become out of spec from wear. But that is only a guess since I don't have the advantage of inspecting the car or perform a simple test such as bumping the pulley with a hammer while the ac is on to determine if it is an air gap problem. Here's a video as to how to fix an air gap problem.

https://www.youtube.com/watch?v=DNx0X4INfiw&t=1106s

[andrewwynn]

Op I think said the system was purged and fill was attempted (can’t get more than about 1/3 the required charge when compressor if not running).

You will be well advised to have the pressure manifold on when you jump start the compressor but when hot wire doesn’t kick it on, clearly something wrong with the clutch or magnet.

It could be as simple as a broken wire.

Unfortunately it will be so much easier to figure that out on a bench than in the car.

I would pull the compressor and investigate the clutch mechanism for an obvious electrical fault like element wire broken off the power tab.

[andrewwynn]

I know that my wife’s AUC was non existent (unplugged) for over a year and her AC worked that whole time. Are you trying to say I was imagining that her AC was working?

I pulled codes and got a code saying AUC nonexistent. Looked and sure as hell I forgot to plug it in after some job where I had to remove the fan shroud.

Back to the topic at hand: AUC has no bearing on the direct drive of the compressor like I mentioned: if you activate the compressor with a scanner it’s relying on electronics and could fail to run even if the clutch is ok.

Direct power fails you have identified the problem it’s the compressor clutch assembly in some way.

Does it click? Well than it’s more likely the clutch plates than the electromagnet. No click than a fair chance just a wire broke off a magnet and could be repaired.

[upallnight]

Originally Posted by andrewwynn

I know that my wife’s AUC was non existent (unplugged) for over a year and her AC worked that whole time. Are you trying to say I was imagining that her AC was working?

I pulled codes and got a code saying AUC nonexistent. Looked and sure as hell I forgot to plug it in after some job where I had to remove the fan shroud.

Back to the topic at hand: AUC has no bearing on the direct drive of the compressor like I mentioned: if you activate the compressor with a scanner it’s relying on electronics and could fail to run even if the clutch is ok.

Direct power fails you have identified the problem it’s the compressor clutch assembly in some way.

Does it click? Well than it’s more likely the clutch plates than the electromagnet. No click than a fair chance just a wire broke off a magnet and could be repaired.

Nope, I'm saying that that "Sparky" bypass the "AUC sensor" before applying power to the compressor. If the AUC has no involvement in the ac system why did he bypass the "AUC sensor"? Did "Sparky" check the air gap?

[andrewwynn]

Sparky took a shortcut and went right to "does compressor clutch work".

I have had to short out failed open low pressure switch so I could charge a system, and I would not be surprised if an active test "engage compressor" still respects the safety of the low pressure it could fail to engage so you wouldn't know if the compressor engages.

It's very logical to start at "will the compressor kick on when voltage applied" there's nothing wrong with that methodology as long as you know it runs off of positive 12v.

[Stevo96]

Cheers guys, it’s booked in the garage on Monday, I’ll report back.