Haywire Electrics - 308 GTI 2020

[bilbopug]

At the weekend I disconnected my battery to route a power cable for a small amplifier. I followed the reset procedure noted on the site but had a horrendous experience when i connected it all back up. Hand brake failure alarm, engine fault warning, service flashing, window shut itself and wouldn't open locking was half working, when I tried to start the engine it was sounding like it was choking and failed to start. Could not get the ignition off.

Anyone know what may have caused this, could it be I just missed a step? Lights (may) have been on auto when I disconnected, but side lights put on as instructed.

In desperation I tried the reset again but no joy so I connected a battery charger as I think it MIGHT be on its way out as econ mode always comes on fast and stop start has not kicked in since I bought the car about 8 weeks ago. I went inside for a while, tried the spare key and after a some attempts of ignition off on, locking , it seemed to just sort itself out and I took it for a spin. Mirrors were funny at first but now are fine. The only issue left with is that there was no sound this morning but when I went back now there was. I dont think its the amp as that was fine in the car I transferred it from.

Anyway, I want to take the battery out to do some tidying up but I am petrified it will happen again. Any advice much appreciated.

I am going to get the battery tested and probably get the garage to change it if required.

[GiveMeABreak]

Just make sure you haven't tapped into any electrical wiring whilst doing your amp work - The electrical systems are not tolerant of any interference unless they are approved and correctly wired. I'll assume you've wired everything directly to the relevant fusebox unless you say otherwise.

The likely issue may be your battery - these need changing at about 5 years.

The BSI reset won't do any of the things you've mentioned, but a weakened battery can cause erratic behaviour.

[bilbopug]

Thank you, I connected the amplifier to the stud in the engine bay fuse box and earthed to the bolt at the side of the dash as per the attached pictures, that should be okay right? It all seems fine now touch wood.

[bilbopug]

No sound again when I got in the car after work, but pressing and holding the phone key which rebooted the Nac wave 2 head unit restored the sound, hopefully it sticks.

[bilbopug]

Battery at 12% health and way down on cranking power although it would start fine. I have had the battery replaced and now its obvious that was needed, from the interior lights to puddle lights alone.

So is it possible it was a low battery caused the cars brain fart?

I feel a bit more confident now about taking the battery out given there were no issues when the new one was connected.