Dual Zone AC not functioning correctly

tharptroy · 10-10-2013, 12:36 PM

2009 335i

When I try to cool the car, the passenger side vents blow cold, driver side vents blow lukewarm.

With it on Max AC, 90F outside, the passenger side vent was at 48degrees, driver side was at 85 degrees. All of the dials are set to cold, so I am fairly certain that it is not operator error.

This tells me that there is likely some valve in the system that is mixing hot air with the cold air that is going to the driver side.

Does anyone have any protips for tracking this down, or know a good place to look for the schematics of the AC system?

Would such an issue show up on any BMW code scanning device?

I made it through summer already, so I have some time to troubleshoot this.

Thanks in Advance!

Tom K. · 10-10-2013, 10:12 PM

A common symptom of an incorrectly charged BMW AC system. Check refrigerant level and leaks.

Tom

tharptroy · 06-19-2014, 10:14 PM

so as a follow up to this post, I waited the entire winter to have the AC serviced.

I took it to a shop, surprise, it was out of freon.

They vacuum checked the system (OK), charged the system, and then put a sniffer device in the vents, told me my evaporator core was probably leaking.

AC has been working fine for a couple of weeks with just the re-charge, I am curious to see how long it will last.

10-10-2013, 12:36 PM	#1
tharptroy Private First Class 15 Rep 137 Posts Drives: 2009 335i Join Date: Sep 2008 Location: Dallas, TX iTrader: (2)	Dual Zone AC not functioning correctly 2009 335i When I try to cool the car, the passenger side vents blow cold, driver side vents blow lukewarm. With it on Max AC, 90F outside, the passenger side vent was at 48degrees, driver side was at 85 degrees. All of the dials are set to cold, so I am fairly certain that it is not operator error. This tells me that there is likely some valve in the system that is mixing hot air with the cold air that is going to the driver side. Does anyone have any protips for tracking this down, or know a good place to look for the schematics of the AC system? Would such an issue show up on any BMW code scanning device? I made it through summer already, so I have some time to troubleshoot this. Thanks in Advance!
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10-10-2013, 10:12 PM	#2
Tom K. Major General 124 Rep 5,627 Posts Drives: '07 328iT, '13 Boxster Join Date: Mar 2008 Location: Maryland iTrader: (0)	A common symptom of an incorrectly charged BMW AC system. Check refrigerant level and leaks. Tom
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06-19-2014, 10:14 PM	#3
tharptroy Private First Class 15 Rep 137 Posts Drives: 2009 335i Join Date: Sep 2008 Location: Dallas, TX iTrader: (2)	so as a follow up to this post, I waited the entire winter to have the AC serviced. I took it to a shop, surprise, it was out of freon. They vacuum checked the system (OK), charged the system, and then put a sniffer device in the vents, told me my evaporator core was probably leaking. AC has been working fine for a couple of weeks with just the re-charge, I am curious to see how long it will last.
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