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530i no power goin to A/C compressor, dont know what else to try.

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65K views 29 replies 11 participants last post by  rdl  
I
#1 ·
Hi all!

In my 530i, 03 model, M54 engine the A/C is blowing only hot air so i checked the compressor and, the pulley its spinning when engine is on but the clutch plate at the front of compressor stands still.

So i checked fuses, relay under the hood and all working fine. when i press the snow flake button the green light turns on but the compressor does not engage. all settings are set for cold.

I had the system checked by a specialist and said that there is plenty of gas in there, pressure is good and all. Then i went to an auto electrician which scanned for trouble codes and found nothing wrong. Then he checked the compressor and came back with the verdict no power going there.

But all wires seem fine from what i can see. Really desperate to fix this because i live in Australia and summer is already here and i dont know waht else to do except take it to a dealer and be skinned alive for it. If u think dealerships in USA charge you an arm and a leg down under they are not satisfied until you have no more limbs.

So in sumary:

- Fuses check.
- Relay check.
- System at correct pressure with plenty of gas.
- All inside settings set for cold.
- No trouble codes.
- Specialist said nopower geting to the compressor.

I read a few threads but seems that the general advice is refill at proper level etc.
 
C
#4 · (Edited)
Assuming you have proper R134a level, the causes of non-engaging AC Clutch are:
1- Bad AC Clutch itself.
2- Bad relay
3- Bad HVAC Panel (in the cabin)
4- ? Bad FSR

Easiest is to find a compatible car and swap items #2, 3 and 4 and report back.

PS: Fuse #75 controls the Aux Fan and has nothing to do with the AC Clutch electromechanical device.
 
C
#7 · (Edited)
Review the following diagram:

1. The HVAC Control Module sends a signal to the AC Clutch when told to do so.

2. However, the pressure switch is connected in series, this means too low or too high pressure of R134a will not allow the AC Clutch to engage.
Did your mechanic over-charged the R134a?

3. Check all fuses as mentioned previously.

4. Last check is the HVAC module.

Again, best is you have a buddy with similar car so you can swap these items for free!

PS: Fuse 75 controls the Electric Aux Fan. With Fuse 75, Aux fan runs correctly. Without Fuse 75, Aux fan not running, engine may overheat during extreme days like >100F.
But the lack of Fuse 75 will not disable the AC Clutch.

Image
 

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I
#8 ·
Thanks for all your replys, been really busy the last couple of days had no time for net or car, but tomorrow i will definitely be looking into it following each advise and report back.

The pressure is at correct levels according to the A/C specialist.

Poolman, that fuse you are talkin about is that like a single black wire with a cilynder plug at the end ? Because the auto electrician guy stuck the tip of a voltmeter tool through the wire about half way and thats when he said there is no power going to compressor.
 
#10 · (Edited)
If I'm not mistaken...the e39's HVAC system is very similar to the e38...perhaps something can be gained from the information below. The E38's HVAC system was a movement away from the systems used in the e32/e34/e31/e24...and many of the features mentioned below were incorporated into the e39 & e46 when they debuted:


Image

Image
 
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#11 ·
IMa530 said:
Hi all!

In my 530i, 03 model, M54 engine the A/C is blowing only hot air so i checked the compressor and, the pulley its spinning when engine is on but the clutch plate at the front of compressor stands still.

So i checked fuses, relay under the hood and all working fine. when i press the snow flake button the green light turns on but the compressor does not engage. all settings are set for cold.

I had the system checked by a specialist and said that there is plenty of gas in there, pressure is good and all. Then i went to an auto electrician which scanned for trouble codes and found nothing wrong. Then he checked the compressor and came back with the verdict no power going there.

But all wires seem fine from what i can see. Really desperate to fix this because i live in Australia and summer is already here and i dont know waht else to do except take it to a dealer and be skinned alive for it. If u think dealerships in USA charge you an arm and a leg down under they are not satisfied until you have no more limbs.

So in sumary:

- Fuses check.
- Relay check.
- System at correct pressure with plenty of gas.
- All inside settings set for cold.
- No trouble codes.
- Specialist said nopower geting to the compressor.

I read a few threads but seems that the general advice is refill at proper level etc.
Click to expand...
I had a very similar issue and I did not see you check your... AUX FAN,, if your AC is turned on... your AUX fan must turn on as welll.. if AUX fan does not turn on.. then the compressor does not either.... and therefore you have no AC... my connectors to the aux fan was corroded in the front near the grill... area.. and what they did was.. re-did the connections to my aux fan and bam..... my AC started working and compressor kicked on.... so check that out.
 
I
#12 ·
Ok, today i started checking everything again:

- Inside all settings set for cold, yes little wheel showing 3 blu dots.
- Fuses in the glove box look all good none with melted or burned whire. (Can not locate #75)
- Aux fan spins normally.
- Checked that black wire that goes into the compressor which then disapears into a bigger bunch of wires and no signs of corrosion or damage.
- Open again the relay box under the hood and checked all the relays in there (no diagram that shows which one is for A/C).

Now cn90 and QSilver7 have advised to check HVAC control module, but before i go ahead and take it out what exactly am i looking for? I am supposing i do need to take it out. All buttons do work though.

Another question is that i checked the relays by shaking them, a mate of mine said that if they rattle the armour inside is broken, but i read on the net that is not the best way to check and i am supposed connect the plus and minus on the realy to the battery and if it makes a noise like clicking that means realy is ok.

Now does anybody know which one is the exact relay? there is a blue a green and a big brown one and how should i check it properly. no other friends that drives a bmw for me to swap.
 
C
#13 · (Edited)
FYI,

1. The Electronic Box on the passenger side (USA model) contains the following items: ECU, TCU, wiper relays, Aux Fan relay etc. but not AC Clutch fuse/relay.
As QSilver7 pointed out above, no relay for AC Clutch.
See pic below for E-box layout (I took that pic from my other posts on wiper relay).

2. Check your Fuse #75/76 though. Search forum for exact location. Basically in the glovebox area.

Image
 
I
#14 ·
cn90 My electronic box only has three relays, the two up top and the bigger one the brown one at the bottom, but mine is more towards the left. Then has another three relays where the fuses are in the rear of the car above the battery.

I will look again for #75 and #76 though i looked all over the glove box. But my aux fan is working so is there a point checking them? i will anyway.

Thanks, for clearing that relay issue with me because i really thought i had a relay problem and as it turns out i have no relay at all for my A/C clutch. I sholud have understood that from qsilver7's diagram but i just didn't click at the time.

Well now all its left to do is take out the HVAC control module and check that all wires are good. I will report on that later on.
 
#16 · (Edited)
Your problem could be simple as a bad connection to the aux fan as mentioned earlier by Flyboyy. Or, could just be a bad aux fan. I know for a fact on later years cars, if your aux fan is bad, there will be no power to the compressor, you can read the codes and it will tell you if you have a bad aux fan or not.
 
I
#17 ·
cn90, my dash shows the correct temp.

16valex, as i mentioned in my starting post after scaning no trouble codes were showing and my aux fan seems to run normal, how can i tell if i have a bad one. Is there a visible connection between aux fan and compressor that i can check?
 
#18 ·
There're only two logics that the aux fan would kick in.
1/ A/C is ON. But your compressor has no power so it can't be from A/C.
2/ Cooling temperatures reaches at a certain point very high though. Did you watch the aux fan spinning under it's own power?

If you are sure that your aux fan is running fine, then I would suggest to by pass the pressure sensor to see if the compressor kick in or not. How? ( short out the sensor where the dryer is)
 
I
#19 ·
16valex sorry these questions might sound stupid, but i have no knowledege about A/C system and never really understood electrics.

Is this sensor on the compressor? i checked the forum but hardly found anything. If i understood correct i need to bypass this sensor and if A/C kicks in then sensor is at fault.

If it is on the compressor does that mean that if taken out freon will come out?
 
#20 · (Edited)
Ima530,

Here are some pix for you.
The first picture is your pressure switch for your A/C. It's located under your right headlight.
The second picture is the location of the plug to your aux fan. Check this plug for corrosions.
I think you should find an A/C expert.
You still haven't convinced me that your aux fan is really working.
 

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I
#22 ·
:DThanks for the advise guys.

Yesterday i had the HVAC panel out, checked all wires and they looked good no signs of corrosion, melting etc, main plug looks good no rust just bit of dust around the whole unit. i even opened the panel to clean the little magnetic rotor (found the DIY for it in this forum). Put it back on. No other friend drives a BMW so a swap its hard to find.

As for the R134 for level im sure the A/C gus knew what he was talkin about, he is part of a bigger shop called southernbm they specialise in bmw but just as expensive as dealership thats why i pulled back after just the diagnosis and thought to tackle it myself before i leave may next paycheck to this guys.
My car has hit the 200k mark in KM's and i have changed all tensioner pulleys, belt, the water pump (flushed whole system) and steering pump, changed oil and spark plugs, hell i'll even do the vanos seal soon (done it before on my Holden GM) but this time i think im out of my league, this is as deep as i go, to much electricity for me.

I will take it for a professional repair and report back where the fault was.
 
I
#23 ·
16valex, i owe you a beer mate, when u come down under let me know:thumbup:

That aux fan plug wasn't pushed in properly, i was checking it and visualy it looked ok bu then i thought ill disconnect it and check for corrosion inside following your advise, so when i was goin to unplug it, it just came of very easy, thats not normal i thought, pushed it back in i made sure i heard it click. Cranked the girl up, pushed the snow flake button and i had a look at the clutch and within seconds kicked in, cold air followed.

cn90 and Qsilver7 thankyou for your help too, i learned a few things about my A/C and HVAC.
 
T
#28 ·
Guys i am having the same problem and i have done everything that was done on this thread. Looking at the picture above i can locate the switch, but i don't know where the switch is exactly on this second picture. My Fan is not kicking in at all and i replaced all the fuses i found on the thread associated with the AC or Aux Fan. I could not however find an Auto store close by that has the relay available but i did notice that the one for the rear defogger located in the truck had the same part number and looked to be exactly like the one one for the AUX fan, my question is, Has anyone tried to swap them out to see if that works ?

Help me please i am in Texas lol
 
X
#29 ·
Hey everyone. I***8217;m having a similar problem. I have a 2007 BMW 530i. My dad has replaced the temperature sensors, a relay, and just today replaced the electric fan. Still no cold air. He said the compressor isn***8217;t getting power. He mentions something about getting an A/C Pressure Sensor and replacing it. I would really like some advice before I dish out more money though. Any thoughts or ideas? It***8217;s hot here in Alabama, lol.
 
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