Is this symptoms of final stage unit going bad?

[jamrobin]

Just an additional thought here... when I replaced the capacitor in mine I noticed that the airflow path to the inside temperature sensor was packed full of lint and dust, (looked like the lint trap in my dryer) that really couldn't have been helping the climate control decide what the actual temperature in my cabin was. I thoroughly cleaned it out and it has worked MUCH better since... that can't be the capacitor change since the symptom that made me change it was that it would completely shut off from time to time.

Jamie

[Smove]

That's not true for digital climate control cars, there's a bit more to the circuit in the Final Stage Unit. It has multiple modes of failure (stuck full on, stuck partially on, oscillates on/off, stuck off).

The potting they used for the FSU expands/contracts too much. With age, it ends up pulling components and/or traces off of the board inside.

Symptoms of the climate control unit going bad are unresponsive buttons, the display blanking out or not turning in at all, button LEDs not turning on.


Gorillajin, I'm 100% positive it is NOT your climate control unit that is bad. It's almost certainly the Final Stage Unit. As long as your blower motor does not make awful noises when it does decide to work, your blower motor is more than likely ok.

Great advise Earthwormjim , any idea where the FSU is before i disassemble the glovebox area looking for it. The only available video on Youtube was for a blower replacement and that was done from under the hood area next to the windshield (passenger side). My AC is coming on then turning off at will ...much better in colder temperature and the morning but has a mind of its own... LED light displays correctly and goes on on demand (up and down ) but as if nothing was done. then all on it's own turn itself on ion high or low or medium. I ordered an original, NEW, BMW FSU from ebay and wish I did not . I think the after market (BEHR) is better. after all my car is 3 years old and did this already.

Thanks

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I replaced the FSU, and it fixed my problem. Thank you for all the advice!

any idea where the FSU is before i disassemble the glovebox area looking for it. The only available video on Youtube was for a blower replacement and that was done from under the hood area next to the windshield (passenger side). My AC is coming on then turning off at will ...much better in colder temperature and the morning but has a mind of its own... LED light displays correctly and goes on on demand (up and down ) but as if nothing was done. then all on it's own turn itself on ion high or low or medium. I ordered an original, NEW, BMW FSU from ebay and wish I did not . I think the after market (BEHR) is better. after all my car is 3 years old and did this already.

Thanks

[anotherhaus]

any idea where the FSU is before i disassemble the glovebox area looking for it.

Stay away from the glovebox; it's under the center console by the drivers' side footwell.

https://www.bimmerforums.com/forum/s...-Resistor-pack

Edit: this thread and those linked instructions are for an E36 M3; if your car is 3 years old it is not an E36 M3, so they may not apply.

If the car is 3 years in your care but is an E36 M3, it is extremely likely that your FSU has failed if you're experiencing any weird climate control symptoms. It's extremely common.

[Smove]

Anotherhaus , thank you for your reply.
I have an F 10 (2014), so the link is for older model. I hope we are correct and it is the FSU... we will see but do not know where exactly to go disassembling first.

[ben4bama]

typically, symptoms of bad fsu is one fan speed despite trying to vary it. if the fan isn't blowing air then that is typically the fan. you can try banging on the cowl when the fan is supposed to be blowing and see if it starts blowing..if it does then its the fan. I've replaced 2 fans and 1 fsu so I'm familiar with these.

[Smove]

ben4bama, fan works great when it works and at full speed sometimes but something slows it down until it stops. It works again in colder temps then stops ... do you have an F10 model ? if you do, where is the FSU reached from . Dealer guy said from under the hood and under the blower. but I do not know if they were saying that to make it sound hard. Estimate labor charge is 2.5-3 hrs

[Smove]

Dealer said yesterday it is under the hood under the blower (Back under the windshield Passenger side on F 10). I do not know if they are trying to sound hard, their labor charge is close to 3 hrs

- - - Updated - - -

Stay away from the glovebox; it's under the center console by the drivers' side footwell.

https://www.bimmerforums.com/forum/s...-Resistor-pack

Edit: this thread and those linked instructions are for an E36 M3; if your car is 3 years old it is not an E36 M3, so they may not apply.

If the car is 3 years in your care but is an E36 M3, it is extremely likely that your FSU has failed if you're experiencing any weird climate control symptoms. It's extremely common.

Dealer said yesterday it is under the hood under the blower (Back under the windshield Passenger side on F 10). I do not know if they are trying to sound hard, their labor charge is close to 3 hrs

[ben4bama]

I don't have an F10 but the fan in my e90 is behind the glove box. My e36 fan is under hood under cowl, the fsu in e36 is under dash on driver side.

[earthwormjim]

Anotherhaus , thank you for your reply.
I have an F 10 (2014), so the link is for older model. I hope we are correct and it is the FSU... we will see but do not know where exactly to go disassembling first.

If you have a 2014 F10, isn't it still under warranty?

I wouldn't be so sure it is the FSU in that car. BMW changed the potting material in the 2000's, to not be so rigid.

[scooper]

what and where is this capacitor located in the obd2 climate control unit that people mention?