Final stage resitor

[RapatchouX5]

My X5 has a defective AC. when I start the engine, the AC fails to deliver air from the front vents while the rear vents are working fine. I can hear the fan spinning but no air coming from the front vents, like something is obstructing the airflow (I feel air from the footwell vents and the rear vents)

Depending on my luck, the time needed to have AC cooling from the front upper body vents is ranging from 30 seconds to 5 minutes.

The AC compressor has been changed last year as well as the final stage resistor based on the advices from this web site. I have the followign questions:

1. How can I ensure that my final stage resistor has failed/ is broken and must be replaced?
2. What is the final stage resistor? What is the job of that part in the A/C system?
3. BMW is advising to change 8 fan motors for an amount of UD 2,500 but I refuse as my fan motors are working, they just need time to do their job.

Thanks in advance for your help

[asawadude]

Hopefully, I'm reading your problem correctly. You're getting cold air out of your rear seat vents, but nothing is coming out of the front vents, so we know that your A/C compressor is working.

The way I can figure it, the FSR measures and regulates cabin temp by controlling the fan speed. The only way to determine if your FSR is the culprit is to replace it with a new unit or from another X5. I've had two of them fail, one in an '00 540i, the second in my '02 X5. In both cases, there were revised BMW FSR units replacing the original parts, so depending on the year of your X5, the original part is probably defective. The new one goes for $75USD.

It's a do it yourself replacement. No need to go to the dealer. Here is the X5world article on how to replace the FSR:

http://www.xoutpost.com/articles/x5/m...placement.html

The article is located in the Miscellaneous section of the X5world homepage.

[RapatchouX5]

Many thanks for your answer.

FYI, after starting the engine with the A/C on MAX, the is no air coming from the front upper vents during 1 to 5 minutes but I can hear the fan spinning. Then after 1 to 5 minutes, the A/C is working normally. I have this problem only with the front vents.

My X5 is a 2002 4.4i model

Thank you in advance for your help

[SuperGreg]

Replace the resistor again and life will be back to normal

[Zulu95]

If the fan is working during those minutes where is the air going? If it is blowing somewhere else then it is a problem with the circuit that decides where the air blows. I had an Audi with that problem and it was a known failure of the GM made Audi Climate Control head unit. It would blow cold air at all speeds but just on the screen.

[motordavid]

Originally Posted by SuperGreg

Replace the resistor again and life will be back to normal

[RapatchouX5]

Hello everyone and many thanks for your feedback.

To answer ZULU 95's question, yes the fan is working immediately after starting the engine and the air is going on my feet and on the rear. After a few minutes, A/C works normally (my only problem is these few minutes without A/C in a very hot country during spring and summer).

YES it is blowing somewhere (feets and rear) and it really looks like a problem with the circuit that decides where the air blows, it blows but not where it is important, the main front vents.

I'll change the FSR and let you know

[Zulu95]

Sound like the Climate Head unit is defective but for your sake I hope the FSR is actually the problem.
Those head units do not come cheap!
GL.

[RapatchouX5]

Hello everyone,

I had the Climate Head unit changed a month ago and my A/C is now working fine

I still do not understand why the BMW dealer advised to change 8 fans motors.

Thank you to everyone for the opinions provided and to the X5 world team, you are doing a great job.