HVAC fan controls don't work

[Bdc101]

Just replaced the unit with a working eBay version which originated in a 2008 4.8i car, but which realoem says is equivalent.




I fired it up and exact same behavior. Works fine except the fan speed doesn't change (except when you hit defrost and it goes to full blast). Everything else still works.



Got a couple of good buttons out of the unit but still need to fix the problem or the wife is going to make me sell it.. any other ideas???

[andrewwynn]

I thought FSU was replaced so I didn't suggest but that's the most common fault when you only have some fan speeds at some times.


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[workingonit]

Originally Posted by andrewwynn

I thought FSU was replaced so I didn't suggest but that's the most common fault when you only have some fan speeds at some times....

I hope mine doesn't start giving me this problem; I've been trying to fix the similar "only have some fan speeds at some times" problem on my wife's '98 GMC, for several years now. 3x resistors (FSU), 2x blower motors, and 2x heater/AC control panels in 3-4 years hasn't fixed it (parts cannon doesn't work, I guess).

I have to either

• 1) whack the control panel with my fist,
• 2) rapidly switch speeds several times with the knob,
• 3) turn the A/C off for awhile and restart it,or
• 4) give up until it starts behaving of its' own accord.

So far, my X5's A/C is like new, comparatively.

[Bdc101]

Originally Posted by andrewwynn

I thought FSU was replaced so I didn't suggest but that's the most common fault when you only have some fan speeds at some times.


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Yep, that was the first thing I did.

[andrewwynn]

Do you have access to a spare? Or unplug and replug. A recent thread where similar symptoms fan can't to life after "exercising" the FSU plug

[Bdc101]

I replaced the battery and now the fan works. Here's the full explanation: https://www.bimmerfest.com/threads/h...#post-13937944

[andrewwynn]

Awesome and good feedback for the next guy! Lots of crazy happens with low battery. The resent FSU thread the guy had a non function FSU until he power cycled the thing which I guess you also coincidentally did.


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