Can anyone identify this fuse for me? Battery draining in 2 days

[AppleAssassin]

I've had a look online and found different answers for some reason. I'm fairly certain the one to the right of it is power steering and the black one on the left is the alternator.

I'm sure this one is the supply for the interior of the car but would like confirmation.

The reason I'm asking is because I've got a bit of battery drain, somewhere in the region of 300-500ma with that wire connected, but goes down to 50-70ma with it disconnected.

If it's the interior supply at least I can begin to narrow down where the drain is coming from.

Thanks.

 

[RUM4MO]

It might help if you tell us the age of your car and which model/engine is in it - it is not by any chance a 2009 1.4 16V Petrol is it?

 

[AppleAssassin]

It might help if you tell us the age of your car and which model/engine is in it - it is not by any chance a 2009 1.4 16V Petrol is it?

Whoops sorry. It's a 2010 1.4 TSI Cupra

 

[RUM4MO]

I was just trying to check if it was a specific age/version of Ibiza that from personal experience, did/could have an issue with incorrectly coded BCM.

Getting fault codes for every controller read is always a good first move, then taking it from there.

One thing to understand is, while that lead probably is supplying the areas of the car that are causing this issue, you have 2 or sometimes more fuses that are providing power to a controller that is allowing power to get "wasted", first the fuse protecting that controller or controllers, and secondly the fuse or fuses that protect the power outputs that that controller or controllers is outputting power to function/functions. I've dived down the "lets stop this happening" and so "locate the source quickly" - and failed miserably, in my case there were no logged faults any where in that car, just battery that ended up getting drained over a few days of not being used.

One approach that I think is helpful is, is to leave the car with the bonnet open if possible, until the controllers have all gone to sleep, then measure the current being taken from the battery - you need to be smart to be able to do this without ending up wakening up any/all the sleeping controllers. My chosen method is to connect one side of a current meter to body/earth using a croc clip, then connect the other side of the current meter down onto the battery -VE post with a sharp long probe, while holding it down firmly, slacken off the battery earth lead and slip it up and so off the -VE battery post, then check the current flow. Noise or rising/falling current usage will either waken up controllers or stop them going to sleep, that can be caused by trapped wires, chaffed insulation or faulty door locking mechanism(s).

You need to able to find a way to allow all the controllers to go to sleep and stay asleep by isolating devices, good luck!

 

[AppleAssassin]

I was just trying to check if it was a specific age/version of Ibiza that from personal experience, did/could have an issue with incorrectly coded BCM.

Getting fault codes for every controller read is always a good first move, then taking it from there.

One thing to understand is, while that lead probably is supplying the areas of the car that are causing this issue, you have 2 or sometimes more fuses that are providing power to a controller that is allowing power to get "wasted", first the fuse protecting that controller or controllers, and secondly the fuse or fuses that protect the power outputs that that controller or controllers is outputting power to function/functions. I've dived down the "lets stop this happening" and so "locate the source quickly" - and failed miserably, in my case there were no logged faults any where in that car, just battery that ended up getting drained over a few days of not being used.

One approach that I think is helpful is, is to leave the car with the bonnet open if possible, until the controllers have all gone to sleep, then measure the current being taken from the battery - you need to be smart to be able to do this without ending up wakening up any/all the sleeping controllers. My chosen method is to connect one side of a current meter to body/earth using a croc clip, then connect the other side of the current meter down onto the battery -VE post with a sharp long probe, while holding it down firmly, slacken off the battery earth lead and slip it up and so off the -VE battery post, then check the current flow. Noise or rising/falling current usage will either waken up controllers or stop them going to sleep, that can be caused by trapped wires, chaffed insulation or faulty door locking mechanism(s).

You need to able to find a way to allow all the controllers to go to sleep and stay asleep by isolating devices, good luck!

Thanks for the detailed reply. I spent 3 hours this morning trying to properly narrow down the source of the current draw. Connected my multimeter in series with the negative of the battery and the earth strap, closed the driver side door latch and then waited 20-30 minutes or so for the current to settle.

Initially I thought it may be the aftermarket Chinese android headunit, but I "fixed" that about a month ago when I added a switch in line with the permanent live. I then disconnected it completely and the current didn't change.

I then started looking at potential fuses it could be and tried pulling fuse 21 which is "Lights control, instrument panel" and it dropped down to about 120mA draw.

Not great but certainly better than 300mA draw. At that point my multimeter switched off and I had to turn it back on and one of the leads came off the battery so had to restart the test with waiting for everything to go to sleep but it went back to 300mA, even after reinstalling the fuse and then taking it out again after waiting.

It's bizarre. I tried pulling literally every fuse and got down to 50-70mA with all the fuses pulled.

Fuse 21 and fuse 17 ( Number plate light /Dimmer /Side light indicator light) gave the biggest drops but it isn't very repeatable i.e pulling them out doesn't immediately cause the current to drop.

I'm honestly tempted to give up and install a battery disconnect switch to save the headache and the cost of getting an autospark to have a look at it

 

[RUM4MO]

I handed the 2009 Ibiza 1.4 16v SC into SEAT eventually, hoping that they would find nothing, as I had then search for the BCM S/W match, and apply it. That did not go very well, they immediately diagnosed that the steering wheel position sensor that on these cars that still have hydraulic-electric steering system only triggers the front fogs at slow speeds, I think that they were just guessing, so that cost quite a bit and that car ended up draining its again, then before I could get it booked back in, that dealership closed as its owner knew that selling the land for housing would work better for him. So after examining everything that I would, I chatted with the other local SEAT dealership service desk and luckily, they had had a traded in VW Polo of a similar age with the same problem - and had requested tech help from VW Mothership, which pointed them to this issue with BCM and where to find the S/W match - so I was very lucky, eventually getting it sorted out there cost 1 hour diagnosis + 0.75 hour to apply the fix, from then on everything was okay.