[Cathaldublin]

So came home, parked the car, come back about 8hours later and it’s just completely dead, like no power to anything, no starter, no clock, nada, even with jump leads attached, or booster pack, nothing, drivers door is stuck closed without the central locking so I can’t get at that fuse box but can get at the ones under bonnet and the relays under dash and nothing obviously blown, all relays and fuses check out fine
I’m reading 9volts on the battery so it’s very dead, it’s on a charge now but suspect somethings shorted so as soon as I reconnect it’ll probably do nothing.
Anyone any ideas of how I troubleshoot, is there a main fuse in the door jam fuse box, I didn’t think so


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[Cathaldublin]

Sorry I should have said booster pack is warning me of a short but without access to the fuse panel on the door it’s hard to pull all the fuses out to narrow down where it might be. If I pull the 428 relay under the bonnet I can power up the booster but nothing works with that disconnected, still that helping me.
Anything obvious I can check, alternator and starter cables look ok but I’ll disconnect them now and check as I think they’re the obvious ones


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[adam-]

Put a decent battery in, go from there.

 

[Cathaldublin]

Put a decent battery in, go from there.

Battery is a Bosch and is less than 3 months old, not being funny but putting a new battery into a car with an obvious short/electrical fault is just a waste of money and time.
It’s out of the car charging now but as the booster is reporting a short I’m trying to find if there is anyone who’s had similar short to check the obvious


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[adam-]

If it was a 'short' you would know about it - it would be on fire. How did you get the bonnet open with the door 'locked shut'?

Why did it get a battery? New batteries can just fail. Get it charged, put a multimeter across it, measure resting and charging voltage, measure current draw when locked and alarm set.

 

[Imagewerx]

Moved to the correct technical section where questions such as this should always be placed.

 

[Cathaldublin]

If it was a 'short' you would know about it - it would be on fire. How did you get the bonnet open with the door 'locked shut'?

Why did it get a battery? New batteries can just fail. Get it charged, put a multimeter across it, measure resting and charging voltage, measure current draw when locked and alarm set.

COULD be on fire. But if something was shorted on a lower amp circuit and for some reason not blowing the fuse, could just have a melted wire or fuse box, if I could open the door I could gain access.
New battery in January as it was off the road for 18months, and couldn’t hold a charge, I can open the passenger door with the key, just not the drivers one as the tension on the lock is too much, common problem but I can’t pop the clip off the handle to open it.
I have the battery charging in the garage, I’ll stick the meter on it tomorrow before and measure current car is drawing when I hook it up, hopefully get something out of the car even enough to use central locking.
I would have expected the booster pack to at least supply enough power to use C/L but as soon as you turn it on it keeps flashing that the terminals are crossed which is why I assumed somethings shorted as I’ve never seen it do that before.
I’d be delighted if it was just the battery as it’s under warranty but I have my doubts


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[adam-]

Disagree. Any wire with a direct short to ground would melt out and fail very quickly, if not going on fire first. You do not have a short. A fuse would protect that.

Could easily be a failed alternator and it had enough charge when you parked it up.

 

[Williamv6]

Run a multimeter across the terminals and see what voltage your getting, It could be a battery issue or an issue with wiring to the battery. Check all your earth connections running from the battery termal.

 

[Cathaldublin]

So after fully charging the battery it was powering no issue and kept a charge fine overnight but checking the amps being drawn when off they were quite high and randomly going up to 1.15ish and back down. I don’t know how long it was like this but the interior lights would flicker for as long as I remember.
There was a dodgy repair on the alternator cable that a Roadside assist guy had done about 8 years ago and I never bothered cleaning it up but I noticed while the engine was running if I wiggled that or the cable next to it that they were arcing.
The one on the left in this pic the plastic was previously burnt and the cable was clamped to the remaining fuse but the one to the right of it wasn’t always making contact.
Once I re crimped, cleaned and retightened them up nice and tight the amps would settle when stopped after a second and no arcing when wiggled. So guessing it was never properly charging when driving and was lucky it lasted this long

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[Cathaldublin]

Not perfect, I could do with a better crimp but it’s all they had in Halfords and it’s tight and the cable is supported so there is no tension on it


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[adam-]

So not a short.

 

[Cathaldublin]

So not a short.

Still confused why the booster was reporting wrong polarity, but fine now


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[adam-]

When they get so discharged, they'll report all sorts of weird things.

 

[alfiesadog]

And people lambast French electrics... lol

 

[northpole]

And people lambast French electrics... lol

that is because that happens with them way earlier than it ever would with a German car, remember the mk4 golfs are now at least 18 years old... so yeah at some point you'll have some electrical cables that'll need replacing and to be fair that batterybox mounted fusebox is known problem.

 

[alfiesadog]

Not knocking the quality, I like German cars mind, but at least the insulation on our old Xantia & 306s is still flexible after 24+ years. The worst of the issues are generally a crusty earth point

Yes that fusebox is a nice feature in theory, but in practice it creates more issues than it prevents. In fairness though, I think a lot of the problems with that are due to rough handling & abuse during battery maintenance along with corrosion when folk invariably break the lid off.

 

[northpole]

Xantia and the 306 are both from when they finally stepped up their wiring game... I used to own a 205 1.9 gti.... it was 10 years old and I got it at a steal because of wiring problems...

 

[alfiesadog]

Haha yes, I had a Junior 1.8D and on many occasions it'd act like the battery was flat only to need the main earth cleaning... again... (point of possible interest/amusement here, when the main earth was in it's fault state & you went to crank the engine the return path was through a small earth wire going to the fuel filter head. it could be seen to twitch with the excess current)