Technical Wiring fault

The Imaginative Lad

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May 27, 2018
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Hi, today the yellow bulb indicator lit up on my dash board. After some investigation their are no bulbs which are blown, I've even checked the rear number plate lights. Now I believe I have found the problem, the left lighting setup has three bulbs which are indicator, brake and tail light.

When I turn on the headlights, the rear tail lights turn on as expected but on the left light setup the brake light also lights up which I assume shouldn't happen as it doesn't with the right lighting setup. The bulb warning light only turns on when I press on the brakes. Both bulbs work fine, just the issue with the left lighting unit.

I've attached images of the problem.

Any idea on how to fix this?
 

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OP
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The Imaginative Lad

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It could be that there is high resistance which sets off the off the warning but the bulb still works.

Sent from my CLT-L09 using FIAT Forum mobile app

Yeah, but that's not the problem. The problem is that the brake light lights up when I turn the headlights on, this bulb doesn't work when I press the brake pedal but turns on when I turn on the headlights.
 

multipete

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Remove the bulb and check it is the right bulb and fitted correctly. If all ok,check earth to that lamp,move black wire in tail light socket. Remove socket and check terminals for corrosion.
 
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The Imaginative Lad

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multipete

The bulb hasn't been changed recently, I have checked the terminals for corrosion. The problem goes away when I move the cable loom connecting to the lighting unit, but then comes back again once I put the unit back into place. How do I get to expose that cable loom? Do I need to pull back the ceiling?
 

Bernievarian

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Jan 15, 2017
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MOST of the time, lights coming ON when other should is caused by bad grounding (return path). The loom goes down the floor, not the ceiling …

BRs, Bernie

If someone here helped You fix -or better, understand- your issue, hit the thanks icon @ bottom right corner, it's free and makes us feel helpy ;-)
 
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The Imaginative Lad

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So figured out what it was, the tail light bulb for the opposite light cluster had blown, which was making the left cluster go crazy and lighting up both bulbs. The moment I had replaced the bulb on the opposite lighting cluster the problem stopped lol. The connector on the left side is a tad faulty but some electrical tape has sorted that out, it was shorting and making the indicator blink across all three lights lol.
 
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