L322 Problem with a little fan inside AC front panel

Hi !!! I ve been listening a noise behind the AC front panel and finally I decided to open it and check it.
There is two boards in it , and in one of them there is a little fan to Cool the board that Never stop running, even with the car key disconnected, and consume battery.
I d like to know if someone can tell me if changing the board or the complete AC front panel this could be solved or if there is any possibility that there is another electric issue outside the board that cause that this fan never stop running.
Thank you !!!!

fpeivissa said:

Hi !!! I ve been listening a noise behind the AC front panel and finally I decided to open it and check it.
There is two boards in it , and in one of them there is a little fan to Cool the board that Never stop running, even with the car key disconnected, and consume battery.
I d like to know if someone can tell me if changing the board or the complete AC front panel this could be solved or if there is any possibility that there is another electric issue outside the board that cause that this fan never stop running.
Thank you !!!!

View attachment 206278View attachment 206279View attachment 206280

Click to expand...

The fan is supposed to run constantly with the ignition on. It's not for cooling the PCB, it's for sampling the cabin temperature for the aircon. Is should shut down eventually with the ignition off, not sure how long that might be on your car as the BCM takes quite a long time to go to sleep.

I'm pretty sure (as Keith says) mine goes off with the ignition.

However, If you lock the car with yourself in it (undo a window just in case it won't unlock you don't want to be stuck in!) press the 'lock' function on the key again quickly once locked to disable the interior movement sensors so you don't set alarm off, sit in there for 10 -15 mins, monitor and check when the gear lever (RED LED) illumination goes out.....the fan should definitely be off by then as all systems are shut down...

Hi, I did it already I was for 45 mins in the car and the fan never stop. Also after one night you open the car and you can listen to the fan, the sound sometimes seems like is going to stop but sound like a failure and start again. Thank you

robhew86 said:

I'm pretty sure (as Keith says) mine goes off with the ignition.

However, If you lock the car with yourself in it (undo a window just in case it won't unlock you don't want to be stuck in!) press the 'lock' function on the key again quickly once locked to disable the interior movement sensors so you don't set alarm off, sit in there for 10 -15 mins, monitor and check when the gear lever (RED LED) illumination goes out.....the fan should definitely be off by then as all systems are shut down...

Click to expand...

Datatek said:

The fan is supposed to run constantly with the ignition on. It's not for cooling the PCB, it's for sampling the cabin temperature for the aircon. Is should shut down eventually with the ignition off, not sure how long that might be on your car as the BCM takes quite a long time to go to sleep.

Click to expand...

Thanks !!! yes that is was I supposed too, but I was waiting in the car for 45 mins with windows closed, and the car locked with the ignition off and without the key and never stop..Also I know is consuming battery because after a couple of days with no use the car needs a booster to turn on, with a new battery with just a week old.

I know when ever I open my 02 door the fan is running but it has never drained my new battery which is 2 weeks old. It possibly starts up as soon as you unlock the door and so it appears to always be going!!!

I had a similar problem fan running battery going flat heater control not working has should, I changed final stage resistor that solved my problems.