Body control unit

[bradley]

Could anyone tell me if a bcu cause a car to lose its charge over a few day.

[trikey]

Unlikely, you need to check each fuse to see which one is drawing current when everything is switched off.

This will give you an idea of where to look.

[marinabrian]

Originally Posted by bradley

Could anyone tell me if a bcu cause a car to lose its charge over a few day.

Yes if it doesn't go to sleep, however this is normally caused by the LSM preventing the BCU entering a dormant state

Take a look through the window after dark, and see if the LSM is illuminated

Brian

[bradley]

What it is I took it to an auto electrician today after buying 3 batteries and having the alternator checked,he said something about the bcu and he's gonna have this bloke in pontypridd to check it on his computer just hope it ain't gonna cost much.

[bradley]

Originally Posted by marinabrian

Yes if it doesn't go to sleep, however this is normally caused by the LSM preventing the BCU entering a dormant state

Take a look through the window after dark, and see if the LSM is illuminated

Brian

What's a lsm brian

[Dorset Bob]

It's the switch to operate the lights.


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[marinabrian]

Originally Posted by bradley

What it is I took it to an auto electrician today after buying 3 batteries and having the alternator checked,he said something about the bcu and he's gonna have this bloke in pontypridd to check it on his computer just hope it ain't gonna cost much.

Would you like to know how many BCU units I've encountered with an actual fault of any description??????





The answer is none at all

The LSM as pointed out is the light switch, and if the background LED lighting is illuminated continuously, it prevents the BCU from entering standby, meaning the current draw is circa 2.5 A, rather than the normal 40mA.

The test for this is to look through the window with the car locked up, and see if the symbols around the light switch are lit up

Brian

[bradley]

Originally Posted by marinabrian

Would you like to know how many BCU units I've encountered with an actual fault of any description??????





The answer is none at all

The LSM as pointed out is the light switch, and if the background LED lighting is illuminated continuously, it prevents the BCU from entering standby, meaning the current draw is circa 2.5 A, rather than the normal 40mA.

The test for this is to look through the window with the car locked up, and see if the symbols around the light switch are lit up

Brian

Well I been out to see if the LSM lights up and the light goes off I've disconnected the satnav in the boot see now if that solves it