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Help!! Strange Climate Control Problem e39

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14K views 8 replies 7 participants last post by  Foodfight  
#1 ·
Hi guys, I am new to the forum, and I tried search the new google, other forums, etc., nobody seems to have a same problem as I do.

So one hot morning I started my car and noticed my climate control unit was dead, and hot air was blowing at my feet even with my car completely off, so I disconnected the FSU connector to stop the air blower. Checked my fuses they were fine, so I figured my climate control unit is dead. Few days later went and bought another, it worked fine, until the next morning when I parked my car outside of my work in the sun. After work started my car and my climate control is dead again, NOTHING WORKS. Drove home, parked my car. Next morning started it and it works again. So it only works when my car is cool NOT THE ENGINE but the car itself, when it does not sit in the sun.
So my climate control unit works in the morning, then after it sits all day in a sun at my job it does not work, then when I get home in the evening and let is sit for few hours it come back on again.
And one more thing i noticed when I leave my car and I turn my fan speed completely off, and when I start the car back on fan speed starts at 1,

I searched the net and couldnt find anyone with the same problem, So if anyone has any idea what could possible be wrong or what should I check, I would really appreciate it, I checked the wires in the back of the unit they seem to be fine.
 
#2 ·
It sounds like symptoms of a faulty FSU.
I would replace that before anything.
 
#3 · (Edited)
I won't pretend to know what wrong with your climate control but it sure seems like the FSU is bad & needs to be replaced. Why don't you do that as a start of your diagnosis. FSUs have caused some weird symptoms.

Edit-Please don't buy aftermarket junk. Get one from the dealer or a respected BMW parts company.
 
#5 ·
Hi Almatyk,

I have the same issue as yours.
1 fine night the alarm goes on and stops by itself.
Next morning i get into the car the blower is at its full speed blowing air on the feet, Climate control Unit dead (the button has lights when head light is ON) but not functional.
To stop the air to flow removed the fuse 9, ordered for a new FSU (reading the posts of FSU failure), replaced it but the issue is the same. Climate control still dead and blower is at its full capacity.
If FSU is fine the Climate Control unit could be the culprit, but dont wanna spend on new Climate Control unit before confirming so.
Expected resolution should be --
> New CCU when connected should be operating good (AC / Heater / fan speeds)
> the blower should act normal with the FSU installed.

Could some 1 please confirm if the Climate Control Unit for 2002 BMW 525I could be diagnosed and repaired rather then ordering a new CCU.

Thanks for your suggestions.
 
#7 ·
And one more thing i noticed when I leave my car and I turn my fan speed completely off, and when I start the car back on fan speed starts at 1,
Let me just add that this is normal. You will never be able to turn off the climate control completely. After the car goes to sleep and wakes up again, the AC will come back on with fan speed at one bar.
 
#9 ·
I had similar symptoms on a 2001 525i. The Climate Control Unit display went blank and the blower would ramp up to full speed and continue running even with the car turned off. I had to pull fuse 9 in the glove box to make it shut off. I bought a used Climate Control Unit on eBay (~$150). This fixed the problem.