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Weird 3rd Brake Light Problem

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10 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW

Discussion summary

YOUR RESEARCHWeird 3rd Brake Light Problem

Leading reported evidence

Replace bulbs

Performed · outcome unconfirmed

No successful repair reported for this finding.

0
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0
Unsuccessful attempts
1
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Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

Discussions that performed work without a confirmed outcome
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Discussions that contain suggestions
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0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Performed · outcome unconfirmed

I changed my bulbs to LEDs and I recall having to install the "tailed" 3rd brake lights just opposite from the normal 3rd brake light...

Weird 3rd Brake Light Problem

Suggestion

You can pry the housing open slowly and replace all the bulbs.

Weird 3rd Brake Light Problem
Read full discussion summary

Leading evidence: 'Replace bulbs' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Replace bulbs' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.

Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.

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1 matching discussions · 10 captured posts examined · 0 partial discussions

Compare 2 other evidence results

Test light and the female plug

Suggestion or failed attempt

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context

Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

Hooked up a test light and the female plug for the body 3rd BL has no juice.

Weird 3rd Brake Light Problem

Test with the wing up

Suggestion or failed attempt

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context

Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

I was doing all my testing with the wing up.

Weird 3rd Brake Light Problem
Frequently discussed actions (3)

These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.

Replace bulbs

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that performed work without a confirmed outcome
1
Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Performed · outcome unconfirmed

I changed my bulbs to LEDs and I recall having to install the "tailed" 3rd brake lights just opposite from the normal 3rd brake light...

Weird 3rd Brake Light Problem

Suggestion

You can pry the housing open slowly and replace all the bulbs.

Weird 3rd Brake Light Problem

Test light and the female plug

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

Hooked up a test light and the female plug for the body 3rd BL has no juice.

Weird 3rd Brake Light Problem

Test with the wing up

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

I was doing all my testing with the wing up.

Weird 3rd Brake Light Problem
Coverage and how to read this overview

Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.

10 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.

  • Rennlist: 1 discussions

0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.

0 acknowledgements have no verified action link; they do not establish a repair result.

Generation: 20261026T155324Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

2001 C4 I noticed that 4 of the 16 LEDs in the body 3rd brake light were out. I removed the whole thing and ordered a replacement. Raised the spoiler so I could still have a 3rd brake light. Decided I did not want to drive around with the spoiler up so I pulled the light from the spoiler and installed it in the body....... it doesn't work. Put it back in the spoiler and it works fine. Put the original body light back in the body and now none of the 16 LEDs work at all. All of the rear tail/brake lights work except the 3rd brake light in the body. Hooked up a test light and the female plug for the body 3rd BL has no juice. No idea where I screwed the pooch on this one. Looks like under the hood is a long black plastic cover with four fasteners. Do those just pull out or do they unscrew? Can that plastic cover be removed without taking the entire intake off? (Looks like a very snug fit.) Where does the wiring for the body 3rd brake light run to? Maybe I can test it there before I start pulling too many panels. Should have been such a simple fix. Thanks in Advance.

POST 2 / ORIGINAL POSTEROriginal post

OK how about this? Can anyone answer this part for me? Looks like under the hood is a long black plastic cover with four fasteners. Do those just pull out or do they unscrew? Thank you

POST 3 / ORIGINAL POSTEROriginal post

Ha. HA! HAHAHA!!! I figured it out! So it appears that when the wing is up, the power to the body third brake light is cut off. When the wing is down the power is restored to the body light and cut off from the wing light. I was doing all my testing with the wing up. So now as soon as my new brake light arrives they will both be working. Hope this helps someone else in the future.

POST 4Original post

Well I'll be dang. Who woulda thunk it. Well obviously the sneaky German Engineers. I woulda spent some time running in circles with this too as I never see the back of the car with wing deployed and brake lights on etc. Thanks.

POST 5Original post

Quotes source post: 12438734

This has happened to other members, probably many times.

POST 6Original post

If your 3rd brake lights are LEDs, there is a good chance the polarity on the connector on the tail is wired opposite of the normal (non tailed) 3rd brake light. I changed my bulbs to LEDs and I recall having to install the "tailed" 3rd brake lights just opposite from the normal 3rd brake light...

POST 7Original post

Why didn't you order the replacement prior to removing the 93% functional one and embarking on this strange and fantastic trip? I believe OP may have omitted this critical first step: "Loaded 150mg of meth into my pipe. Smoked it."

POST 8Original post

Well, those 3rd brake lights are not LEDs. They are small bulbs. You can pry the housing open slowly and replace all the bulbs. I forgot what type of bulbs they are but I got my replacement bulbs from o'reilly. They are common bulbs type and I think they are 8 bulbs in that 3rd brake light housing.

POST 9 / ORIGINAL POSTEROriginal post

Quotes source post: 12439964

And we have my first ignored member. 😀

POST 10Original post

I figured your first ignored member was in your trous...eh, never mind. Happy tweeking!

This is a source reference. Confirm exact model applicability in the original material.