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I bought a 2007 model ML350 4matic in October last winter. Of course, I didn't check the air conditioner then. It's summer now and the air conditioner wasn't giving out even the slightest bit of cold air.
I went to the air conditioner and they checked. They said there is no leakage, but they said there is no freon left in the system.
They added Freon and the car started blowing cold air.
I hit the road and soon realized that the system gave the outside air instead of the cold air.
Then I tried a few times, the compressor seemed to turn itself off. When I turned the car off and on or waited for a while to idle, it would turn on again when I turned the AC button on and off.
After all, I tried it all night. Compressor does not turn off at all at idle, working so good. When you start using the car, it turns itself off after a while (approximately 2 minutes). when parked it starts to get cold again.
What do you think could be the problem?
I have attached a video of my problem. When idle pressure is 10-12bar, when driving car pressure will 6 bar.
And there is no DTC Error fault code.
Car Started . A/C closed. Ref. pressure 8.5bar. Evap temp 23degree 60sec after a/c on. Evaporator temprature is 2degree and its really cold. Ref. Pressure 11bar Driving car pressure will down / temprature will hotter still gives cold air but not as idle. driving. pressure will down 6bar. no more cold air.
I think I found the problem, the air conditioner did not work at all for the last 2 days and yesterday, while driving on the road, there was a cracking noise from the engine.
I opened the hood and there were pieces on the crankcase protector. When I paid attention, I realized that the part was the air conditioner clutch.When I searched the internet, I was sure it was the part.
I'm going to buy a new A/C clutch. However, I couldn't find any clear information about the replace.
Can the clutch be changed while the compressor is on the vehicle?
Do i need to evacuate the air conditioner freon r134?
Do i need special assembly experience?
My problem continues. A/C works fine, cools very fast and well (better than my other audi) but turns itself off after a while, then turns on again etc. it works randomly.
There is no error code.
I renewed the air conditioner gas.
I replaced the A/C clutch (it was broken once before and it never worked when broke)
I checked with xentry today. The results are below; My last decision is that it will be related to energy management. Because the battery of the car is old and its power is low. but I don't want to change the battery without being sure. because I think it works fine.
Check my Xentry adventures
start of test sequence system closed AC will activated after 1min it cools very good. system pressure is 14bar it asks actuation is ok. if i choose ok test will finish. if i said no; it says it needs to be fault code 9006 9007 but there is no fault code. it says it needs to be fault code 9006 9007 but there is no fault code. i cant check them. i said no. It lists the reasons i checked; ac button is ok tempature sensors are ok coolant is not 110c its ok i only suspect "ME switches off the AC compreassor for high power requency" while this test AC is not blow cold weather i check this test again, you can see the result; AC is active but evaparator temp is 24c, it blows outside weather, system has 7bar (is it problem??) now system working fine, pressure is 9.5 bar. (i understand it didnt need to be 14bar for work fine? )
So, on your 4th screenshot the display describes what's expected to happen after actuation test.
Compressor is requested 100%, cold air should be lowing from vents, and refrigerant pressure should rise.
Then it asks you did these things happen (test successful)?
I thought you'd said all these things happened. So why would you say No?
Anyway, for those where the test did not make these things happen the only causes left are:
9006: Short or bad connection of signal to compressor control valve, or faulty compressor control valve. (It's mounted to the compressor housing but can be replaced or you can run a diode jumper perhaps. The diode rectifies the PWM signal for the valve to operate for a variable amount of compressor pumping effort)
, search this site for more on 9006.
9007: Bad compressor (I think is what this code means)
I would think 14 Bar is less than normal for full cooling. But it might not be very hot outside where you are.
I thought you'd said all these things happened. So why would you say No?
Actually i said YES, but when i press the YES, it ends the acutation test and says everything is ok. Because of this, i press NO for see what happens if its not ok.
and AC block has no fault codes like 9006 or 9007. When i press NO, it says you should see these codes.
Today, I went to the repair shop to replace the steering hose and I saw that the air conditioner power line was a single cable and was slightly damaged. There was no electrician in the repair shop.
is it normal that there is only one cable entering the air conditioner? Maybe that's why the problem is.
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