Any Climate Control guru's?

tbenesch · #1 08-03-2009, 01:59 AM

2002 X5 4.4L. Just got back from the beach and had to experience driving in hot and humid weather with a climate control issue and was hoping someone might shed some light. We had the AC on and it was blowing nicely and cold. Then I noticed that the air wasn't coming out of the vent as much as it previously did. The fan is still going strong, but only a slight amount of air was coming out of the vent (although it was cold air). I had replaced the Final Stage Resistor (2nd time) just before we took off to the beach as I thought that was the culprit. So the fan works fine (I can hear it going to town full on), the air that does escape from the vents is cold, so the AC portion works. I just don't know much about what the climate control does. Is there something behind the vents that closes/opens to allow the air to come through the vents? Is there a fuse that I can take out that will allow me to manually control the air? This is really irking me and I'm at a loss on how this whole thing works. The rear vents don't even emit a breeze although the fan is going full blast. There's something there that is restricting the air from escaping and if I can only find it to open it up.... Thanks for any insight. This is an intermittent problem. When I restart the car, the fan is blowing hard and cold.

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Gary92 · #2 08-03-2009, 02:22 AM

try checking behind the kidney grill if the vents are opening fully when you have this problem

m5james · #3 08-04-2009, 12:57 AM

Replace or completely remove the filters. I know in my 7 there are two 6"x12" filters on the bottom side of the hood, then two more under the dash on each side that are about 4"x6". I'm guessing the X5 should have these same cabin filters.

Weasel · #4 08-04-2009, 02:20 AM

Sounds like you may be freezing over... Since you had the ac on max cold in a humid climate the humidity that was wicked from the air may have frozen to the evaporator thus restricting airflow. It would melt quickly if yoou turned the system off for a few minutes if this is the case.

In this case the problem could be the ac charge being a little off, but more likely the evaporator case temperature sensor not reading correctly. (only has to be off by a couple degrees)

m5james · #5 08-05-2009, 12:16 AM

I've still got my money on clogged filters. If anything take a quick and easy 10 minutes to remove the filters to see if it helps...if not, then you've got other things t try.

Weasel · #6 08-06-2009, 08:51 AM

Clogged filters would easier to spot as it would be all the time, and the air volume would change when switched from inside air to outside air.

If the air volume only drops after having the ac on blowing cold for a while, but the fan speed sounds normal, and the air volume returns to normal after having the ac off for a while... I'd primarily suspect freeze over. The moisture condensed from the air by passing through the evaporator (this is what drips on the ground with the ac on) can freeze to the evaporator blocking airflow through it.

m5james · #7 08-06-2009, 03:08 PM

Touche. Any results?

billybushby · #8 08-09-2009, 04:38 AM

I have the same thing, but what I have been told is this happens because it is how climate control works and is meant to happen. Don't ask me why but that's what BMW dealers techno warrior told me when he looked at it and said there's nothing to worry about? So far it's never failed so I suppose I have to believe him until something goes wrong and that's been a year now

anerbe · #9 08-11-2009, 10:16 AM

there are motorized door flaps inside the HVAC system. they adjust to regulate temperature. to rule these out, manually change the venting to blow forward (not windshield or floor). Also set your A/C on max/coldest setting, and you can have your windows open to avoid the temperature sensor adjusting based off inside temp. The doors should be fixed in the face/forward air position, and shouldn't change. If you don't see any variation, and the ac still blows cold and hard, you could have a temperature regulation issue (sensor perhaps) that is changing the doors to stop blowing forward. typically, the system responds in auto by blowing more forward/face when colder air is needed, and then transitions the air to top/windshield when hotter air is needed. this is to avoid frosting over the windshield.

if you still see this variation in airflow, weasel could be right on the evap freeze. in very humid temps, the evap could develop frost, and when it does, it will just keep compounding, reducing flow.

pedson · #10 08-19-2009, 01:34 PM

Did you ever resolve this issue? I have the same issue with my 2001 x5

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