19 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHMalfunctioning Turn Signal Light
Leading reported evidence
Replace bulb and bulb-holder
Performed · outcome unconfirmed
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 performed work without a confirmed outcome
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 · Original poster
Swapped bulb and bulb-holder from right to left (bulb and bulb holder individually and as one unit).
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
Checking continuity between pins from the plug on the housing to the spring-clip terminals inside the headlight housing, where the bulb-holder plugs in:
Leading evidence: 'Replace bulb and bulb-holder' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check continuity between pins' (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.
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
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.
Outcome qualification: Negation, uncertainty or missing explicit repair resolution overrides the raw extraction signal.
Set aside this weekend
Performed · outcome unconfirmed
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 performed work without a confirmed outcome
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 · Original poster
I have set aside this weekend to try everyone of them, as well as using CRC electronic contact cleaner aerosol.
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
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 · Original poster
Both L & R bulbs are tested individually and test OK
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
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 · Original poster
2.Bulb is OK (had to remove the complete headlight assembly); replaced it with a new one (tested just to be sure.)
These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.
Check continuity between pins
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
Checking continuity between pins from the plug on the housing to the spring-clip terminals inside the headlight housing, where the bulb-holder plugs in:
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
Adrian Headlights have a DYI kit to repair & replace the wiring inside the headlight; this involves the nasty job of heating and removing the lens, which is not for the faint-at-heart.
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 have to test this some more but if confirmed, would necessitate either opening the headlight assembly and repairing the wire, or replacing the whole assembly.
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.
19 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 · 1 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261026T135432Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
The Left Front Turn Signal Light on my 2002 C4 Cab has suddenly stopped working. Here are the details:
1. Fuses are OK (#B2 and B6 on the fuse panel in LH footwell.)
2.Bulb is OK (had to remove the complete headlight assembly); replaced it with a new one (tested just to be sure.)
3. Bulb terminals of the twist-type bulb-holder are fine; no corrosion or loss of spring effect. Contact terminals inside the cavity where they touch the terminals on the bulb-holder are clean and corrosion-free.
4. The plug-in harness module goes in and out freely, and the male pins (on the headlight assembly) and the female receptors (fixed inside the cavity) show no sign of corrosion or damage
5. The stalk correctly activates all functions it controls, except for the front LH turn signal.
6. The LH Rear signal works, but flashes at a rapid rate.
7. The Hazard Light switch works all lights except the LF turn signal light. The two green directional arrows on the switch blink normally.
I have repeatedly removed and reinstalled the entire light assembly/module, bulb holder, and bulb to no avail.
Would appreciate any insight, knowledge, guidance or experience you can share.
Long shot but check the flasher relay. Then I would start checking things with a multimeter. I would start with the bulb socket first, making sure you have 12V and a good ground in the socket.
Are you certain the connector on the back of the headlight is seating properly in the receiving connector mounted in the headlight tray? I had a similar issue and discovered a crack had developed around the receiving connector in the tray. When I push the headlight assembly back into the tray and locked it in, that crack allowed the receiving connector to flex backward slightly. It was just enough flex to keep some of the contacts from seating completely. Replacing the tray fixed it.
Did you try swapping the bulb holder between left and right? I had an issue where the bulb holder wore away the contact to the headlight assembly�� the bulb holder is available from the dealer��
-Eric
04 996
Thank you all for great suggestions so far. I have set aside this weekend to try everyone of them, as well as using CRC electronic contact cleaner aerosol.
Ok, here is the progress report based on the suggestions so far:
1. Swapped bulb and bulb-holder from right to left (bulb and bulb holder individually and as one unit). They both function correctly (i.e., they light up on the RH side, but not on the LH side.)
2. The female plug at the end of the harness from body inside the fender is securely attached to its tray and does not move. The wire terminals (+ and -) on this plug for the LH turn signal function correctly. They receive power from the stalk and blink correctly.
So, power is delivered to the plug at the headlight assembly, and the bulb holder and bulb function correctly, but do not function when inserted into the respective receptor in the headlight assembly. The problem seems to be either the spring terminals which touch the bulb holder, or the wires form the pin at the male plug to the terminals at the bulb holder.
I'll keep on trucking and report back.
Thank you for the link to the video. I had reached the same conclusion (see my last post above, last paragraph), and I will perform those tests and report back.
TODAY'S UPDATE
(11/10/25)
I am stumped and at my wit's end. Need some serious help short of replacing the whole headlight. Here is a summary of what has been done so far:
1. Both L & R bulbs are tested individually and test OK
2. Both L & R bulb-holders are tested individually and test OK
3. The terminals inside the headlight where the bulb-holder plugs in have been tested and moved in (to ascertain full contact) as shown in the video posted by
Tommelton.
4. The power and ground are present at the appropriate pins on the plug from body harness. Externally connected a bulb/bulb-holder to these pins, and the turn signal blinks properly.
5. Have connected power directly to the +/- pins on the white plug on the light assembly module. The bulb does not come on.
The problem of "no LH turn signal blinking" persists.
I have repeated the above steps 2-3 times, and hate to conclude that the fault lies within the headlight module, either the wires or terminals that are not visible through the bulb-holder opening.
Any further thoughts and suggestions are still most welcome.
Bahman
More testing update today:
Checking continuity between pins from the plug on the housing to the spring-clip terminals inside the headlight housing, where the bulb-holder plugs in:
Full continuity from + pin on the plug to the spring-clip terminal inside the housing (the one closer to inside)
No continuity from - pin on the plug to the spring clip terminal inside the housing (the one closer to outside). The connection from the green wire terminal to the spring clip terminal is solid.
Seems somehow the ground wire is not connecting, and either the headlight assembly needs to be opened up, or a replacement headlight assembly is needed. Neither option is easy to accept.
Thoughts?
Its been a few years and trying to remember, but I had to replace my turn signal stalk on the steering wheel because the turn signals weren't working. At the time it wasn't an expensive part and was an easy fix.
Something else to keep on your mind as well are the ignition switch and headlight switch. While they probably have nothing to do with whats happening with your turn signals, they will eventually go as well and create other problems. Good news is the turn signals stalk, ignition switch amd headlight switch will last you 18-20 years after you replace them.
Good luck with finding the gremlin.
Thank you for your suggestions. I get blinking signal at the point where the headlight harness plugs into the headlight assembly. The problem seems to be in the wire inside the headlight that connects the ground pin at the assembly plug with the spring contact at the bulb-holder base. I have to test this some more but if confirmed, would necessitate either opening the headlight assembly and repairing the wire, or replacing the whole assembly. Neither is feasible.
You may want to reach out to Adrian at adrian tailights. He is a member here as well. He may have an answer and or parts since he specializes in 996 headlights and tail lights.
Contact https://share.google/jVoDBluH8B6QmUc99
Thank you for the lead. I contacted Adrian Taillights (adriantaillights.com) and found Adrian to be very knowledgeable, helpful, and professional. It appears that the insulation of wires inside the headlight have a tendency to degrade by now and cause shorts and other problems. This seems to be the problem with my headlight.
Adrian Headlights have a DYI kit to repair & replace the wiring inside the headlight; this involves the nasty job of heating and removing the lens, which is not for the faint-at-heart.
They also have a turnkey service to install the kt. There is a 2-3 months waiting list for this service, and I am opting for it.
A big THANK YOU to all who have provided suggestions and offered solutions.
Cheers,
Bahman
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