2004 L322 3L. BMW DIESEL 97k (no additions or mods the car is "mint" for its year.)
I post rarely on here as frankly the car has given us little trouble that we have not been
able to solve or fix by searching the fantastic archives here, or deal with ourselves, but this one has me puzzled.
ISSUE
Drove the car yesterday (no issues) parked it last night, alarm set, no issues.
This morning I come out to a strange “noise” coming from the car (still locked).
I unlock and pop the bonnet (keys not in ignition) loud noise continues is coming from the area in front of the battery compartment to the right (facing it) of the engine (not the ebox fan fan up behind batt, that runs fine)
Started the car and drove it few miles (no issues) but the noise continues and is just audible in cab at idle. (check control just says OK, I don’t have a diagnostics unit, sorry)
Come home, engine off, ignition on - it continues. Remove key- noise continues, – lock car - it continues. Car goes (to sleep) all systems off – it continues.
Noises are hard to describe but my best description is high pitch electronic squeal like a constant higher pitch buzz or possibly a low pitch whistle/whining sound ?

If anyone has any experience of this issue I would be grateful to hear from you, before I go down the garage route.
TIA

I had a similar problem on our td6. It ended up being the washer motor running constantly. I dont know what triggered the problem, suffice to say that pulling fuses helped eliminate what it was, but it was coming from the area you describe. 2010 L322 Autobiography Black Edition
1975 Land Rover

24 valve, thank you for that reply most helpful.
I have tracked it down, as you say, to one of the 3 wiper motors.
(the nearside one of the 3) Removed headlight and grill to access it.
(thanks to Powerfuluk for the YouTube vid).
Disconnected and removed the affected motor.
I swapped another motor over to the connector and the swap out motor then runs on that circuit.
So, the issue is not the motor itself, it must be further back in the system somewhere.

Anyone with electrics knowledge know which relay or what it could be causing
this particular motor to run independently even when car is locked (alarm set) or with engine running ?

TIA Phil

Following on from the above post, just to wrap this up (as many posts don’t explain exactly how they finally solved their issue.)

The whining “noise” was in the front O/S coming from the farthest O/S water pump on the wash wipe reservoir for the windows f/r and headlights. It was running independently of the ignition being on or off.

On further investigation this afternoon I discovered the front O/S headlight motor was inop. And had a small hole in it, where the casing had melted on the top and water could get it.
Obviously the motor had burnt out, causing the plastic to melt !
This clearly happened some time ago but the short only happened last night.
It may also explain a drain on the battery I`ve been looking for over 4 yrs and as many batteries !

I disconnected the wiper motor, via the plug connector and the noisy water pump on the res. immediately ceased running.
Clearly there is a short inside the front O/S headlight wiper motor, which is making a connection to the pump on the reservoir, making it run.

So, replacement wiper motor ordered, problem (hopefully) solved.

Hope this helps anyone in future.

Best Phil