Air Conditioning not working

[DanielS]

Air Conditioning not working

So after weeks of just being swamped with work, I finally got around to the Z4 again. The airbag issue is still there but I have a appointment with a specialist to sit down on a Saturday to get this sorted. So my next and hopefully last issue is the AC.

When hitting the "Snow Flake" in the car I hear some buzzing going on in the car, but no cold air. So I took the car do a local indy and had the AC system checked. They did a 10 minute vacuum test, pulled out all the old gas, about half full and filled up the system with new gas. Started the car and boom cold air!! So no issues!! Yet on my way back home the AC decided to start heating up the car instead of cooling it down. On the driveway I check the AC Clutch and this engages and properly and I can feel the metal hoses turning warm and cold. Also no error messages in INPA. Now I don't have the tools to do a check on the High and Low pressure, but my feeling is that the compressor has died on me.

What are your thoughts on this? replacing the compressor seems like a s**t job to be honest.

 

[DanielS]

First start the car, air-conditioning not turned on.









And then with the AC working.




I can't seem to find the expected pressure for the E85 anybody got a idea what they should be?

 

[DanielS]

After reading some more about the AC system, I might need to look into the fan that cools the AC Condensor. Something about a green wire that deteriorates over time. Does anybody have any pictures of what I should be looking for?

 

[bigwinn]

I haven't got a pic (I don't think)

But fairly easy to check-

before you strip the front of the car down- you can use INPA to check the fan DOES work- which is the same as checking if the green wire is intact or not I believe

 

[DanielS]

Opened up inpa and it says fan at 100% when I want to change it, inpa gives me a error.

Engine is not overheating and had zero issues there.

 

[bigwinn]

Is it running when at 100%?

If not then I think your green wire is failing or and failed

Pop the front slam cover off the engine you’ll see the main connector on the left hand side of the radiator and fan unit

You can’t miss the green wire

Inspect it and if it’s bad it’s fairly easy to splice a new one in

 

[DanielS]

No it's not running.

Found the green wire, yet not sure what I am looking at. It looks solid. Can I measure the output with a multimeter?

 

[DanielS]

I just stuck a multimeter in the output adapter.

I have a solid 12volt for the 2 big wires and about 4,5 volts between ground and the smaller wire. Is this about correct?

Anywhere else I should look before figuring out how to remove the fan?

 

[enuff_zed]

I know this is probably a daft question, but have you tried the fan to see if you can spin it?

 

[DanielS]

Never a duff questions, make sure I cover all my bases. 8)

Yes the fan spins freely.

 

[DanielS]

I closed up the car for today in as I have BBQ obligations.

I did read op on replacing the fan here.:

https://www.pelicanparts.com/techar.../41-WATER-Engine_Cooling_Fan_Replacement.htm#

Yet the bottom screw, is there a way to undo this without having get the entire front end in the air and removing the cover?

Also could it be the "Sensor f. AUC" that's causing the fan not to run? Lot easier to replace and a lot cheaper.

 

[bigwinn]

Only two fixings to remove the fan

T27 next to the clip with the green wire
Grommet clip the other side
Undo AUC sensor
Undo electrical connection

Slides up and out

I’ve got a spare if needed?

 

[DanielS]

@bigwinn I thought there is also a screw at the bottom of the fan housing. If looking at the repair manual posted on pelican parts. If it's just the 1 T27 and the grommet that would be great!

How much for the part? (PM?)

 

[enuff_zed]

Also could it be the "Sensor f. AUC" that's causing the fan not to run? Lot easier to replace and a lot cheaper.

I thought I remembered someone on here saying if the sensor tells the car it's outside certain parameters it won't activate the AC.
Searched but can't find it.
Worth a double check though.
How cheap is the sensor? Enough to make it worth buying one first to see if it fixes it?
Just thinking that if you have that code and change the fan but it still doesn't work, you'll never quite know what the issue is, so maybe swap the cheap part first?

 

[DanielS]

The sensor is a common part. Found on a lot of BMW'S.

https://www.realoem.com/bmw/enUS/pa...2.5i&mg=64&sg=45&diagId=64_1265&q=64116917001

So sourcing one online should not be terribly difficult. And replacing would be be just clicking it in. Although you did describe that the AC would not turn on, and that's not the issue. The AC, compressor and everything else just turns on. Except for the fan. Might try getting the fan out later today. See how far I get.

 

[DanielS]

Only two fixings to remove the fan

T27 next to the clip with the green wire
Grommet clip the other side
Undo AUC sensor
Undo electrical connection

Slides up and out

I’ve got a spare if needed?

I used the good old PartyQ on the BBQ so quickly ran to the car with a beer and the men gathered around.

Bigwinn was right!! It's out! Job was like a 10 min thing getting it out. Then another 5 taking the fan apart.

 

[DanielS]

I was lucky, I was able to get a second hand fan for just 40 euro, got delivered today. Installed the fan hooked everything back. Turned on the car.... Suspense.... Hit the snow flake and.... No luck!!!

Inpa is still showing that the fan is running at 100% yet it isn't moving at all!! The AUC unit I cleaned out but it's just a sensor and looked clean.

What control unit controls the fan? There must be something off... :headbang:

 

[DanielS]

As it's beautiful weather right now, I got ISTA-D out. Loaded up the DME and set for a test of the Electric fan and poof! The fan works!!!

So now knowing that the fan works and I can control it via the DME it means somewhere something is not telling it to come on.

Where to look next?

 

[DanielS]

Does anybody know what this is?

It's a picture from INPA with the AC on and loaded settings for the car. "Stellgrosse" it's a minus 300%. Could this be causing the issue of the AC not working and just blowing hot air?

 

[bigwinn]

Translates to adjusting size?