Hi, I have a Ford S-Max Diesel from 2010 that will drain the battery if you leave it outside overnight in cold weather.

Som background facts, that may or may not be useful info.
Now and then a relay is activated and 10A fuse (F8) in the engine compartment is activated and i hear a high pitched whirring sound.
According to this it should be related to "Powertrain control module, fuel metering unit, MAF sensor, fuel rail pressure control valve (engine management)"
It happens every time i open the front door.

Another "symptom" is that whenevery i am reversing, it the alarm for detecting obstacles behind you is beeping, so i have to press the button to disable that since the sound is annoying. That could be due ti me having the towbar attached. but i have not tested not having it attached.

Do you think it the parasitic draw is related to the car wanting to be ready to start when i open the door or walk near the car, and thus engage the F8 fuse.
Could it be some kind of fuel pressure leak that casues the fuel pressure to somehow having to be increased.
Or could it be something totally unrelated to this.

Best regards.
Christoffer from Finland

 

i tested the system with the fuse i mentioned earlier removed, and i saw a 19amp draw, located to a 15A fuse in the fuse box under the glove box.

Will try to see what it is related to

 

So am update, the fuse in the glove box is related to the audio system. and is drawing power.
And the one F8 i mentioned earlier is according to my manual 'antriebsstrangsteuergerät' which is powertrain control unit.
the latter is the one that is whirring when i open the door, and the one for the audio system is the one that is causing a power drain.