Battery being drained

[mickthemaverick]

Because you should do the test with everything switched off

[Sloppysod]

Im just thinking, why do i need a multi meter why dont i pull fuses until dim lights go off?

Who knows? You'll have to work your way through all of them one at a time until you find the one that cuts the current off. I'd start with the easiest to access!

And because, if not found it could turn out to be something serious, which could lead to a failure of a component while out and about or at the worse still an electrical fire.

[gsc1ugs]

Still not solved, here are the lights that stay dim, does it look like an ecu problem?

[gsc1ugs]

[wurlycorner]

The problem with doing a current draw test by just measuring current inline to the battery and removing and refitting fuses, is that each time you do that, you risk ‘waking something up’, disrupting the current draw and giving you a false direction.

You can do a parasitic drain test, using a multimeter that only does volts.
Open all doors, boot and bonnet.
Take the covers off all the fuse boxes.
Manually latch all the locks (so that the car ‘thinks’ everything is closed).
Cover any internal alarm motion detectors with insulating tape (or disable that function via a button if your car has one - check the owners manual).
Lock the car with the remote control and let it sit for about 20 minutes - all the electronics should ‘go to sleep’.

Then go to every fuse in every fuse box and measure the voltage across the fuse (each fuse should have contacts poking out the top, put negative probe on one and positive on the other) with the meter set to millivolts if it isn’t auto-ranging.
You should have zero on basically everything, perhaps some will show 0.001V or similar- that’s ok. Any circuit that is still drawing current will stand out like a mile, something in the 0.01V range or above, is your culprit.
If you note down the rating of that fuse (e.g. 20 amp) and the type of fuse (mini/standard/maxi etc) then you can look up on line and find conversion tables to give you the current draw of that circuit, based on the milliamps you’ve measured.


EDIT: there are lots of videos out there on YouTube showing how to do this, here’s one that covers it quite well.

[wurlycorner]

Is that with the car fully switched off, key removed, doors closed and vehicle locked?

[gsc1ugs]

Yes, take battery lead off they vanished, went through fuses with multimeter nothing drawing on anything 0.000 volts on each

[Peter.N.]

Have you checked to see if the alternator is drawing any currant?

Peter

[gsc1ugs]

No, hows that done?

[Peter.N.]

If you have a test meter with an 'Amps' range, connect it in series with the alternator live lead and set the meter to 'Amp's ( one lead to the disconnected alternator lead and the other one to the battery), it should read little or nothing but if it is showing more than just a few milliamps the alternator diodes or regulator are faulty. It should read virtually nothing but if it is showing half an amp or more your alternator needs attention or replacement

Peter

[gsc1ugs]

Sorry sound stupid but it dont make sense, if alternator lead is disconnected, how can it be testing alternator? Apologies but need a bit clearer info thxs

[Paul-R]

You only disconnect it so that you can remake the connection through the meter.

An alternative way is to disconnect a battery terminal and remake the connection through the meter and measure the current. If you then disconnect the alternator lead and the current being drawn drops then you know you need to look at the alternator.

[gsc1ugs]

What about if i disconnect the alternator surply and see if lights go out?

[mickthemaverick]

That would be a similar test. If you are going to disconnect the charging lead from the alternator then connect that lead to the red meter lead and the black meter lead onto the alternator terminal as in the sketch here:

MTMO

If there is a fault in the regulator inside the alternator then you will see the leakage current on the meter. DO NOT start the engine with the meter connected there as you may wreck your meter!!

[gsc1ugs]

That would be a similar test. If you are going to disconnect the charging lead from the alternator then connect that lead to the red meter lead and the black meter lead onto the alternator terminal as in the sketch here:



If there is a fault in the regulator inside the alternator then you will see the leakage current on the meter. DO NOT start the engine with the meter connected there as you may wreck your meter!!

I get that, time jack van up, amps or mAMps