RS5 Turn Signal Issue: Troubleshooting Light Problems

As someone with moderate experience working on cars, I had a very similar electrical fault on my 2013 S5 last winter. The indicator light symptoms matched yours exactly, warning on the dash and erratic turn signal behavior. After trying basic troubleshooting like checking fuses, I took it to an independent workshop. They diagnosed it as a faulty wiring connection at the front turn signal assembly. The cable insulation had worn through, causing intermittent shorts. Total repair including diagnostic time came to 95 Euro. The electrical fault was actually quite straightforward once properly diagnosed. They replaced the damaged wiring section and connector plug rather than the entire lamp assembly, which saved considerable cost. To provide more specific guidance for your case, could you share: Does the issue occur on both left and right indicators? Are there any other electrical oddities like interior lighting flicker? Have you noticed if it happens more in wet weather? Can you share the exact error message showing on your speedometer? Getting this information would help determine if you are dealing with the same root cause I experienced. These indicator light problems often stem from similar wiring issues across the model range.

Last service done at 190253 KM. The signal lamp problems seem to have gotten worse since I first posted. Now the front left bulb burns out frequently, even after replacement with OEM parts. Each time I replace it, the flasher relay makes an unusual clicking sound before eventually failing again within days. One thing I forgot to mention in my initial post, the fault appears worse during cold starts and the warning message repeats every time I engage the indicators. The bulb replacement itself is straightforward but clearly not fixing the underlying issue. I suspect the automotive lighting control module could be the real problem rather than just defective bulbs. The quoted 95 Euro repair cost sounds reasonable compared to dealer prices. Will try troubleshooting the wiring connections first based on your experience before replacing more expensive components.

Glad to provide a follow-up on my previous repair experience. The symptoms you describe with frequent bulb burnout and relay clicking strongly point to an electrical issue rather than just defective bulbs. After my initial wiring repair, I actually encountered a similar pattern where the turn indicator started acting up again during cold weather. The flasher relay clicking became more pronounced, exactly like what you describe. The root cause turned out to be corrosion in the front indicator housing connector, causing resistance that led to premature bulb failure. The broken lens seal had allowed moisture to penetrate over time. The electrical fault was triggering the error message due to irregular current flow. My suggestion based on this experience: Check the indicator housing for any cracked seals, Inspect connector pins for green corrosion, Clean all ground connections, Test voltage at the bulb socket The repair should cost similar to what I paid before if its just connector related. However, if the lighting control module is failing, expect costs around 300-400 Euro for parts and programming. Let us know what you find after checking those connection points. The cold start correlation often indicates connection problems rather than component failure.

Based on the wear and tear mentioned, I will take your advice about checking the connections first. Just removed the front indicator housing to inspect, sure enough, there is visible corrosion on the connector pins and a small crack in the lens seal, exactly as you described. Going to clean all the connections and replace the broken lens seal this weekend. The frequent bulb replacement was getting expensive anyway, so hopefully fixing these electrical connection issues will solve both the turn signal reliability problems and prevent further premature bulb failures. The voltage testing step you suggested makes sense too, will borrow a multimeter to check the readings before putting everything back together. Smart to verify proper current flow rather than just assuming new bulbs will fix it. Much appreciated for sharing your similar repair experience. Saved me from unnecessarily replacing the whole lighting control module when the fault likely stems from basic connection issues. Will update once I complete the repair to confirm if this resolves the cold start problems too.