Boot Lighting

[tc4332]

Hi Guys,
I have had a scare, I thought that my beloved A8 was going up in smoke.
Some weeks back I replaced the puddle, door and boot lights with LED bulbs. This was OK until last night. Whilst playing with a media player on Aux 2 on the Analog TV unit; I had left the boot open for some ten minutes. I started to smell what I thought was spilled TCP but wifey explained was something burning.
Oh, how my stomach churned. All three boot lights were out. Resolved it to the left hand boot light melting!!!!
The right hand and boot lid lights looked OK, just not illuminated.
I dropped the boot roof lining because the left hand light would not come out of the lining and found the molten mess in the attached photos.
The wires supplying this light were also badly heat affected, molten insulation and stuck together. I have stripped this cable back as far as I could at the time, cut the damaged part out and insulated the two ends. I will have to examine the loom further back to make sure there is no hidden damage.
The boot lid light is now working but the right boot light is not.
The current flow diagram shows all three in parallel so I do not yet know why one light works but not the other.
I am surprised that these lights are not fused but perhaps I am missing something. The current that must have been drawn to cause this damage should have blown a fuse and saved the circuitry.
Any ideas?
Was it the LED faulting, or could the LED have moved causing a short across the light fitting contacts.

[M-A8]

That looks really scary mate.

Not sure what to say really, but when I looked at the pictures first and before reading your post I straight away blamed the LED being left on for too long as they generate quiet a lot of heat quiet quickly.

Is 10min enough to cause this sort of damage, not sure, plus, I'm pretty sure the lights go off within 10min anyway and I have noticed that few times, they wont stay lit for as long as you keep the boot open.

I have similar LEDs fitted and no issues for over 18months at least and I have them as interior lights as well which I've had on for more than 10min on many occasions.

Could short circuit cause so much damage on 12v supply?? I don't know, other more knowledgeable guys will answer this question.

And yeah, in my opinion fuse should go off, I've had fuse for whole interior illumination going off because of something not so dramatic, but first I would check what type of fuse you have fitted in there.
It's possible it happened before possibly because of the wiring fault and previous owner got feed up with changing fuse or had no similar amper one and put a 20A or 30A fuse on a circuit which requires lets say 5-10A

Very worrying and needs further investigating for sure

[ScottD3]

Resister over heated, caught the plastic but never caused enough of a short circuit for the fuse to trip.

Where did you get the LEDs?

[tc4332]

The LEDs came via ChinaBye, so they could be suspect.
I think the "wrong fuse" is worth considering.
I'll look into that as soon as wifey brings the car back.

[ainarssems]

It does look like resistors overheated or possibly a bad connection that arched and overheated. I don't think interior bulbs are monitored for faults, are they? If not then you would be better of with regular, non 'Canbus ready, error free bulbs' as those without resistors will produce a lot less heat.

[M-A8]

Yeah, they are not monitored so it is better to use standard LEDs with no resistors

[tc4332]

When the weather here clears I'll lie down in the trunk and strip the loom and repair as needed. Also will replace these bulbs with cheap standard LEDs
Thanks for the support/suggestions.