AC Does not Cool immediately sometimes?

Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Our database does not have any information on testing the cooling fan which is controlled by the Engine Computer.

Symptoms indicates a possible fault with the fan motor.

As to the AC failing, you need to check if it is loss of refrigeants or a fault in the compressor or controlling system.

If the fan is the cause of the problem, the AC compressor might work for a brief perod of time before it cuts off.

For such jobs, it is best to be done by professionals as any mistakes can be costly.
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Saturday, July 13th, 2019 AT 1:55 PM (Merged)
Tiny
DOCHAGERTY
  • MECHANIC
  • 9,601 POSTS
I agree with my associate that the issue should be dealt with by a BMW knowledgeable technician. If there is an issue with the A/C that was caused by the aux fan being inoperative, then you will need to seek out a local BMW pro, we can guide you, but in the end, the choice is up to you.
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Saturday, July 13th, 2019 AT 1:55 PM (Merged)
Tiny
JIM DONALDSON
  • MEMBER
  • 1 POST
  • 2001 BMW X5
  • 6 CYL
  • AWD
  • AUTOMATIC
  • 125,000 MILES
A/C system does not function. Fan does not run. No cold air produced.

It did this on an intermittent basis for a while and now does not work at all.

Suggestions.
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Saturday, July 13th, 2019 AT 1:55 PM (Merged)
Tiny
MHPAUTOS
  • MECHANIC
  • 31,937 POSTS
Hi there,
Start with the basics, have the system leak tested as low refrigerant is the most common cause of a system shut down.

Mark (mhpautos)
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Saturday, July 13th, 2019 AT 1:55 PM (Merged)
Tiny
DOCHAGERTY
  • MECHANIC
  • 9,601 POSTS
The final stage unit is faulty. Part # 64-11-6-923-204. Go to Realoem. Com for the part. It is a high failure item.
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Saturday, July 13th, 2019 AT 1:55 PM (Merged)
Tiny
BOGS
  • MEMBER
  • 1 POST
  • 2002 BMW X5
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 52,000 MILES
Ac control still lights up but aircon is not working at all, no air is coming out on vent either. 2months prior to this a/c is acting up, vent blows hard then soft and even if the engine is turned off the blower still goes on and you have to turn blower to max then turn it down, only then will it stop. Help and advice appreciated!
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Saturday, July 13th, 2019 AT 1:55 PM (Merged)
Tiny
DOCHAGERTY
  • MECHANIC
  • 9,601 POSTS
The blower motor control unit known as the final stage will require replacement. It is a fairly high failure item and the part # is 64-11-8-385-549. It is accessed through the passenger foot well and removal of the side carpet trim is needed.
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Saturday, July 13th, 2019 AT 1:55 PM (Merged)
Tiny
RPERFETTI
  • MEMBER
  • 1 POST
  • 2003 BMW X5
Air Conditioning problem
2003 BMW X5 6 cyl Four Wheel Drive Automatic

Hello I have a problem with my X5 A/C. I checked the freon and is good but the compressor doesn't start the blower is working bot not cold air.
Somebody have any idea what could happened.

Thanks
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Saturday, July 13th, 2019 AT 1:55 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Is your car's air conditioner blowing warm air only and no cool air? Your A/C cooling problem could be caused by any of the following:

Your A/C system may have lost its charge of refrigerant, or the compressor may not be engaging when you turn on the A/C, or the blend air door inside the HVAC unit may be stuck in the HEAT position so no air goes through the A/C evaporator.

Start with the compressor. Does it engage when you turn on the A/C?

If so, the compressor is working and the A/C system probably contains enough refrigerant to make cold air, so the problem is inside the HVAC unit. Replace the motor that controls the blend air door (this is a difficult job and best left to a professional since it involves tearing apart the HVAC unit -- about an 8 to 10 hour job!).

If the compressor does not engage when you turn on the A/C, see if it will run by jumping the compressor clutch wire directly to the battery (use a fused jumper wire). If the compressor works when you jump it, and the A/C blows cold air, the system contains refrigerant and the fault is likely a bad A/C compressor clutch relay or a bad clutch cycling switch or pressure switch.

If the compressor does not engage when you jump it, the problem is a bad compressor clutch.

If the clutch engages but the compressor does not turn (the belt will start to slip and squeal), the compressor is loced up and you need a new compressor.

If the compressor clutch engages and turns the compressor, but the A/C still does not blow cold air, the system is probably low on refrigerant and needs to be recharged. If you Have an A/C gauge set, hook it up and see if the system has any pressure.

If it is out of refrigerant or is low, check for leaks, then have the A/C system vacuum purged to remove air. After the air is out, it can be recharged with the specified amount of refrigerant. It is important to get any air out as this will reduce cooling efficiency and may make the compressor noisy.

My advice to you if you know nothing about A/C service is to find a repair shop that specializes in A/C repairs and let them fix your cooling problem for you. Today's A/C systems with automatic climate control are very complex and reuire special tools and know-how to diagnose and repair.
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Saturday, July 13th, 2019 AT 1:55 PM (Merged)
Tiny
TURKTUCKER
  • MEMBER
  • 1 POST
  • 2002 BMW X5
2002 BMW X5 6 cyl

Hi. Suddenly my vents do not blow any air/heat, although the lights/buttons on the temperature control panels operate, etc. I replaced all fuses that could possibly be linked and still, no air. I even replaced te Final Stage Unit (Blower Motor Resistor) and still, no air. Any other suggestions on what to check out?
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Saturday, July 13th, 2019 AT 1:55 PM (Merged)
Tiny
DOCHAGERTY
  • MECHANIC
  • 9,601 POSTS
The final stage has been replaced and still no air flow usually means the fan motor has got a bad spot on the commutator and needs replacement as well. Be sure the wiring connector is not the issue here, I have had that happen to me.
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Saturday, July 13th, 2019 AT 1:55 PM (Merged)
Tiny
LARSENS
  • MEMBER
  • 3 POSTS
  • 2002 BMW X5
  • 6 CYL
  • AWD
  • AUTOMATIC
  • 88,000 MILES
Repair shop replaced the AC condensor after the car would only blow warm air. Now on long drives (over 2 hours) the system seems to radiate cool air but will not blow it. Makes me wonder if the system is frozen up or something. Are there controls to baffles that might malfunction or a clutch that would work only when the system is beginning to cool but not later on? Shop can't/won't diagnose the problem since it works fine when we take it to the shop after a short drive. We spent a TON of money on the condensor and don't want to pay for a fishing expedition, dismantling the dashboard again, etc. Without a specific idea of where to direct the repairs. Any ideas on why this new problem would arise? Would be happy to discuss further. Thanks.
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Saturday, July 13th, 2019 AT 1:55 PM (Merged)
Tiny
LARSENS
  • MEMBER
  • 3 POSTS
Your reply deals with lean fuel condition but my question was regarding an Air Conditioning problem. I saw some of your other AC replies on BMWs and you appear to really know your stuff. Can you reply to my AC question? You can hear the AC system working and apparently the fan, and it cools OK for a couple hours but then seems to not push any air through the dash despite the noise. Advice? I saw your earlier posts about a final stage unit or motor for the blend air door. Would those things work for awhile and then quit?
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Saturday, July 13th, 2019 AT 1:56 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
An A/C system that blows cold air for awhile then warm air is probably freezing up. This can be caused by air and moisture in the system that allows ice to form and block the orifice tube.

Evacuating the system with a vacuum pump will purge it of unwanted air and moisture. Evacuation should be done with a vacuum pump that is capable of achieving and holding a high vacuum (29 inches) for at least 30 to 45 minutes.

For best performance, an A/C system should contain less than 2% air by weight. For every 1% increase in the amount of air that displaces refrigerant in the system, there will be a corresponding drop of about one degree in cooling performance. More than 6% air can cause a very noticeable drop in cooling performance, and possibly cause evaporator freeze-up.

Air can get inside a system through leaks, by not evacuating the system prior to recharging it, and/or by recharging the system with refrigerant that is contaminated with air. Recovery equipment can suck air into the recycling tank if an A/C system contains air or if the system has a leak. For this reason, the refrigerant recovery tank on recycling equipment must be checked and purged daily. On some equipment, this is done automatically. But on equipment that lacks an automatic purge cycle, tank pressure and temperature has to be measured and compared to a static pressure reference chart.

Some refrigerant identifier equipment can detect air in the system as well as other contaminants. An identifier should be used to check the refrigerant before the system is serviced to prevent cross-contamination of recovery and recycling equipment.

Possible causes of intermittent cooling in a manual A/C system that might be caused by an electrical problem include:

Faulty low pressure cutout switch. This switch prevents the compressor from running if the refrigerant level is low. If the cutout switch is not reading correctly, it can prevent the compressor from coming on.

Faulty compressor clutch. The magnetic clutch on the compressor requires full battery voltage to engage. If the voltage to the clutch is low, or the clutch coils have too much resistance, or the air gap in the clutch is too great, the clutch may not engage to drive the compressor.

Faulty compressor clutch relay. Check to see if the relay is receiving voltage when the A/C is turned on. Also check the relay wiring and ground connections. If bypassing the relay with a jumper wire or routing battery voltage directly to the compressor clutch makes the A/C work, the relay is probably bad.

Faulty A/C control switch. The switch may be worn and not making good contact when it is turned on.

Some possible causes of intermittent cooling (or no cooling) on automatic A/C systems include all of the above, plus:

A problem in the control module or control head (this usually requires using a dealer scan tool to read fault codes and perform self-diagnostics).

A bad temperature sensor (an ambient air temperature sensor, interior air temperature sensor, evaporator temperature sensor, or sunload sensor). Again, a factory scan tool is usually required to perform diagnostics on the system.
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Saturday, July 13th, 2019 AT 1:56 PM (Merged)
Tiny
LARSENS
  • MEMBER
  • 3 POSTS
Thanks for the fantastic information. I suspected it might be freezing up. It also blew fog for awhile after the condensor was installed and it had been recharged and that might have been an indication of moisture in the system. I will ask the shop to evacuate and recharge the system again.
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Saturday, July 13th, 2019 AT 1:56 PM (Merged)
Tiny
DOCHAGERTY
  • MECHANIC
  • 9,601 POSTS
The E-53 tends to be sensitive to refrigerant amount so that any shortfall is systemically amplified. Be sure the correct amount of R-134 is in the system and the right amount of oil too.
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Saturday, July 13th, 2019 AT 1:56 PM (Merged)
Tiny
CAMELLIAH
  • MEMBER
  • 2 POSTS
  • 2003 BMW X5
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 80,000 MILES
The air conditioning in my 2003 BMW X5 has been on the fritz for a few weeks. Exactly one year ago the A/C broke (explosion with white vapor emerging from under the hood) and I had a new compressor, fan and expansion valve put in. Now suddenly the A/C will not work from time to time. I brought it to my mechanic and after he looked under the hood and said things looked ok the A/C kicked in so he thought I was crazy. Even when the A/C doesn't work I hear the compressor turning on and if I open the hood I see the fan running, but no air (hot or cold) emerges from the vents. Then the next day or a few days later it will suddenly kick in. What gives?
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Saturday, July 13th, 2019 AT 1:56 PM (Merged)
Tiny
DOCHAGERTY
  • MECHANIC
  • 9,601 POSTS
First, thank you for donating. And you seem to have what is a typical problem with the E-46, E-53, E-39 cars. It is called a final stage unit and it controls the fan speed. Replacement is through the passenger footwell area.
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Saturday, July 13th, 2019 AT 1:56 PM (Merged)
Tiny
CAMELLIAH
  • MEMBER
  • 2 POSTS
Thank you! I will ask my mechanic to replace the final stage unit. Can I assume that even if I tough it out with intermittent A/C in the summer, that this will be a problem with heating during the winter? (I live in New England but I am not tough enough to go through a New England winter with no heat!)
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Saturday, July 13th, 2019 AT 1:56 PM (Merged)
Tiny
DOCHAGERTY
  • MECHANIC
  • 9,601 POSTS
You are welcome. The final stage is the module that controls the fan speed, so yes it will effect the A/C as well as the heater as they both depend on the same fan.
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Saturday, July 13th, 2019 AT 1:56 PM (Merged)

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