A/C not blowing cold

[andrewwynn]

That's exactly the problem I suspect here


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[upallnight]

Originally Posted by andrewwynn

That's exactly the problem I suspect here


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But he said he can hear the "Click" and the "Click" is only made when the clutch makes contact with the steel pulley

[andrewwynn]

I was thinking the function was slightly different. That the magnet threw the clutch plate, and the plate can wear like a disk brake and just wears out and doesn't grab?

[oldskewel]

Originally Posted by trhaverstock

I have a 2004 E53 3.0 with just over 105K miles. A/C was working great the other week and now abruptly not blowing cold.

I have a manifold gauge set and am getting around 90psi on both high and low sides with the A/C either on or off. The clutch is engaging when I turn the A/C on and will stop when I turn off. I checked the two 7.5a fuses in the glove box and am good.

I am looking for some advice on what to troubleshoot and hoping for advice it's not the compressor gone bad :-(. I am not well versed on A/C other than adding R134.

Thanks!

90psi on high and low sides:
- the fact that it is the same on high and low means the compressor is not compressing
- the 90 psi means you probably do have liquid R-134a in there along with the R-134a gas. The gas is saturated, and from looking at the 90psi pressure, that indicates a system temperature of 82F. PDF attached here to show the pressure vs. temp relationship for a saturated vapor condition.

forane-134a-pressure-temperature-chart.pdf

If you were to take the same test on a cold engine on a colder day, you'd get a lower pressure. Or on a warmed up engine, where the ambient temp in the engine bay is much higher, you'd get higher pressure readings. All completely normal and expected.

If the pressure were far below what you see on this chart, it could indicate that you do not have enough R-134a in the system to create a saturated vapor. So there would be no liquid, and only gas. Clear indication of insufficient fill. But that's not you.

On the clutch, what exactly makes you think the clutch is engaging? As is being discussed here, maybe it makes a noise, but maybe it does not fully engage. Can you see the shaft actually spinning (or not spinning)? (I don't know if that is impossible to check, but I'll ask anyway )

[upallnight]

Originally Posted by oldskewel

90psi on high and low sides:
- the fact that it is the same on high and low means the compressor is not compressing
- the 90 psi means you probably do have liquid R-134a in there along with the R-134a gas. The gas is saturated, and from looking at the 90psi pressure, that indicates a system temperature of 82F. PDF attached here to show the pressure vs. temp relationship for a saturated vapor condition.

Attachment 78942

If you were to take the same test on a cold engine on a colder day, you'd get a lower pressure. Or on a warmed up engine, where the ambient temp in the engine bay is much higher, you'd get higher pressure readings. All completely normal and expected.

If the pressure were far below what you see on this chart, it could indicate that you do not have enough R-134a in the system to create a saturated vapor. So there would be no liquid, and only gas. Clear indication of insufficient fill. But that's not you.

On the clutch, what exactly makes you think the clutch is engaging? As is being discussed here, maybe it makes a noise, but maybe it does not fully engage. Can you see the shaft actually spinning (or not spinning)? (I don't know if that is impossible to check, but I'll ask anyway )

Could be a misdiagnosis by a DIYer. He think the clutch for the compressor is actuating but it is not.

Here's a video with an X5 as an example on how to test and replace the coil and clutch.

https://www.youtube.com/watch?v=GOrJSSCG-1g

https://www.youtube.com/watch?v=0gVyOnZUfZU

[trhaverstock]

The A/C season came and went and I appreciate everyone's advice. After tinkering for several hours today I think I have this nailed down and need a sanity check from the group. It's a 2004 E53 3.0 with 110K miles.

**I think it is the HVAC control module** and need advice/confirmation.

I can see the clutch kicking on and activating the A/C compressor and see the front part of the compressor spinning very clearly (vs not spinning with A/C off). Vents are blowing *warm* air at normal engine operating temp with Max A/C on.

I got a lead to check the heater control valve. I disconnected the plug for it and it appears grounded well when touching my multimeter to + battery and neg to the valve or valve body.

I checked the heater control valve plug's voltage per https://www.pelicanparts.com/techart...eplacement.htm and I am only getting +0.03 Volts when the heat is set to 90 degrees or I have Max A/C and 60 Deg setting. I am supposed to be getting approx 12VDC when on Max A/C.

Fuse 48 (7.5amp) is good.

The HVAC control module "looks" fine and doesn't act strange in any way but am assuming a bad component or bad solder joint is possible?

Should I attempt to jumper 12VDC to the heater control valve (add 12VDC to the tan/orange wire) to see if I get A/C? Anything else I can check? SHould I pick up a used HVAC control module from Ebay?

[trhaverstock]

Bump for any thoughts............

[trhaverstock]

I want to post my results on getting my AC fixed in hopes it will help someone else!

As the original poster, I had my AC to the mechanic after all unsuccessful attempts to resolve on my own and he wanted to replace $1200 in parts. I asked if he'd be willing to replace the $15 Control Valve (see post from X5StayinAlive at https://xoutpost.com/bmw-sav-forums/...-cold-air.html). He agreed and I ordered the valve. He had a bit of a hard time getting the old out but evacuated the system, installed the new control valve and I am happy to report my AC has been working GREAT for the past week. It ended up running me a little over $150 in labor and materials plus the Santech control valve. It was worth a $150 gamble to me to try the valve before replacing the compressor and other components. I could have done this myself if I had the equipment and knowledge on AC but didn't want to mess things up.

Huge thank you to X5StayinAlive for posting that fix!!!!

[sroth004]

Thanks for posting your solution. I know nothing about AC but will keep this fix in mind if mine misbehaves.


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[andrewwynn]

That's a great share.