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7 Series - E65 / E66 (2002 - 2008)
Discussion of BMW's 4th generation E65/E66 7 Series flagship. The E65 generated much controversy, due to its radical styling and iDrive user difficulties. Nonetheless, the E65 broke records to become the best-selling 7-series iteration ever, especially after its 2005 facelift.

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  #1  
Old 08-27-2015, 04:10 PM
FlylowTX FlylowTX is offline
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Mein Auto: '04 760li '01 750il Sport
Weird A/C issue - Any ideas?

OK, so its 100 degrees everyday around here in North Texas. Not a good time for a/c problems, especially when you have a black on black 760!

My a/c works great on as long as the car is moving, but quits upon slowing down or stopping in traffic. Of course the first thing is to make certain is that the aux fan in front of the condenser is working. Mine IS WORKING - hence the oddity of the issue.

Could it be A) A refrigerant issue i.e. too much or too little B) A weak compressor C) Fill in the blank.

Any a/c gurus out there?

While we're on the subject, it also does the "Takes 3 minutes or so before the a/c kicks in" thing. Only upon a cold start. When the car is hot, the ac works immediately (as long as you're moving at a good clip). Has anyone ever figured this out? I've seen other threads but never a real solution.

I will greatly appreciate any and all ideas!
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Last edited by FlylowTX; 08-27-2015 at 04:19 PM.
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  #2  
Old 08-27-2015, 04:14 PM
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Quote:
Originally Posted by FlylowTX View Post
OK, so its 100 degrees everyday around here in North Texas. Not a good time for a/c problems, especially when you have a black on black 760!

My a/c works great on as long as the car is moving, but quits upon slowing down or stopping in traffic. Of course the first thing is to make certain is that the aux fan in front of the condenser is working. Mine IS WORKING - hence the oddity of the issue.

Could it be A) A refrigerant issue i.e. too much or too little B) A weak compressor C) Fill in the blank.

Any a/c gurus out there?

While we're on the subject, it also does the "Takes 3 minutes or so before the a/c kicks in" thing. Only upon a cold start. When the car is hot, the a'c works immediately (as long as you're moving at a good clip). Has anyone ever figured this out? I've seen other threads but never a real solution.

I will greatly appreciate any and all ideas!


Sounds like a power issue , How old is the battery in your car ?
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  #3  
Old 08-27-2015, 04:17 PM
FlylowTX FlylowTX is offline
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Mein Auto: '04 760li '01 750il Sport
Battery is brand new. Car was doing the "fan won't blow hard, even if I turn it up all the way" thing, and, thanks to this board, I determined it was caused by low battery voltage.

The new battery eliminated the issue, and the fan blows hard like it should. Didn't affect the no ac at a stop problem though...
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Old 08-27-2015, 05:07 PM
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Quote:
Originally Posted by FlylowTX View Post
Battery is brand new. Car was doing the "fan won't blow hard, even if I turn it up all the way" thing, and, thanks to this board, I determined it was caused by low battery voltage.

The new battery eliminated the issue, and the fan blows hard like it should. Didn't affect the no ac at a stop problem though...
Strange ... Did you have the Battery registered when put in ?
Only reason I ask is cause a friends car was doing same
exact thing & new Battery fixed it ...
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  #5  
Old 08-27-2015, 05:09 PM
FlylowTX FlylowTX is offline
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No I haven't yet, but I do have the laptop with BMW software so I will do it. Hopefully I can remember how to do it!

Will report back later with results...
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  #6  
Old 08-27-2015, 06:28 PM
Alika808 Alika808 is offline
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This is a symptoms of the pusher fan not blow enough air to cool-of the condenser. How's the speed of the pusher fan? While you are driving or the car moving, the condenser is cooling-off from the free air coming in front of the car. Check if the condenser for dirt clog-up. Clean with A/C condenser cleaner. How's your clutch fan, it can help the air flow.
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  #7  
Old 08-28-2015, 10:53 AM
FlylowTX FlylowTX is offline
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Mein Auto: '04 760li '01 750il Sport
Good idea on the fan clutch. I will look up a test procedure and find out! Only thing arguing against the fan clutch is that the engine is not overheating in any way, even on the hottest days. Only the ac quits blowing cold upon slowing/stopping.
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Old 08-28-2015, 12:10 PM
Alika808 Alika808 is offline
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The clutch fan is to help the moves front air flow into the condenser but if the pusher is not turning fast enough and the condenser is clog-up then the A/C will not cooling when the car is stationary.
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  #9  
Old 08-28-2015, 07:33 PM
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Rookie2008 Rookie2008 is offline
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Sorry to hear your issues OP. I myself am having this issue with my PT Cruiser. We were 105 today here in SoCal. I'm wondering if its just that hot out causing to a/c to malfunction if you will... Good luck though.
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  #10  
Old 08-28-2015, 07:37 PM
luigi524td luigi524td is online now
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Definitely check that the auxiliary fan (not the engine cooling fan)
is running when your car is sitting at idle. Otherwise your AC will do exactly what it's doing ...
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  #11  
Old 09-17-2015, 04:13 PM
FlylowTX FlylowTX is offline
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Thanks for all the replies!

Hooked up INPA and registered the battery.

Checked electric aux fan, ran it through 14 possible speeds, no problems there.

Noticed that in my ac live data, the refrigerant pressure switch reading was way out of range, i.e. showing a far higher value than the computer looks for.

Unfortunately, to change the switch you have to open up the system and refill it afterwards.

I will eventually replace this switch, as I think it could be whats causing this strange behaviour.

Its $38 at Rock Auto, so at least the part is cheap.
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