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Tail light doesn't work when headlights on but does when running lights on

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

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YOUR RESEARCHTail light doesn't work when headlights on but does when running lights on

Leading reported evidence

Run lights are

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Suggestion · Original poster

I'm thinking this is the headlight switch (because the wiring and bulb work for the same light when just running lights are on), but I wanted to see if anyone had the same issue before I replace that switch.

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Tail light doesn't work when headlights on but does when running lights on
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Leading evidence: 'Run lights are' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Run lights are' (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.

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1 matching discussions · 2 captured posts examined · 0 partial discussions

Frequently discussed actions (1)

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Run lights are

No successful repair reported for this finding.

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Reported fixes
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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'm thinking this is the headlight switch (because the wiring and bulb work for the same light when just running lights are on), but I wanted to see if anyone had the same issue before I replace that switch.

Original post Read captured discussion
Tail light doesn't work when headlights on but does when running lights on
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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.

2 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.

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Generation: 20261026T165820Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

Hi, all, So on the driver side rear light, both the outer and inner red lights work when the running lights are on. But when I move the switch one click over to put the headlights on, the right (inner) red light on the driver's side doesn't light up. I'm thinking this is the headlight switch (because the wiring and bulb work for the same light when just running lights are on), but I wanted to see if anyone had the same issue before I replace that switch. It's a 2001 cab. Thanks!

POST 2Original post

https://rennlist.com/forums/996-foru...placement.html Make sure you get a Porsche switch, not one made in China.

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