AC volume and balance

[longassname]

Originally Posted by andrewwynn

Yeah that sounds like FSU/blower.

Do you have access to a different similar car for a control?

Also "all the way" is rarely helpful long term, but the mix to cold in Florida may be exception to the rule.

Is the problem almost only the air volume? And at what setting for air intensity and what temp?

"Max" is "wrong answer". Start with everything at full auto and fan speed set to intensive, temp set to 74 make sure auto is lit on left and auto recirculation is set.

Then once the front is caught up turn the temp down a couple. I find in 90° heat I need it set to 70-72 here.

Next go to back seat and set to auto and 74. If the fan speed is super high then try 77 until the fan stabilizes. Once the temp gets closer to set the fan speed should slow down.

It "feels like" you aren't getting full speed on the front blower and without a control to compare it's difficult to confirm.

What scanning capability do you have? My scanner will send speed requests to the blower directly.

Do you hear the blower keep speeding up the full range of speed?

If a temp sensor is broken and the car thinks it's colder than reality, that can cause blower speed problems but only on auto and I'm pretty sure you've tried full fan speed or "max" which don't use that will not help you.

I have an icom and istad and istap (and all the rest of the diagnostic software that typically comes on an ssd with bmw diagnostics). With the amount of noise the blower makes I have to believe it is spinning at full speed. My assumption has been that there is a flapper somewhere restricting the overall air volume below what it needs to supply both the front and back.

I try to leave it set to auto, intense, 74 degrees. If the rear ac is turned off that more or less works. Performance isn’t good enough that anything less than intense would be considered.