T-Roc Turn Signal Malfunction: Relay vs Electrical Issue

Had the same issue on a 2020 VW Tiguan. The irregular turn signal behavior often points to either a flasher relay problem or wiring issues in the connection points. In my case, the signal lamp was flashing erratically because of corroded terminals in the main connection plug. The automotive lighting system shares several ground points, and when these get compromised, it creates these symptoms. The broken connection was causing the turn signal to misfire or stay illuminated. The repair involved cleaning the connector pins and replacing a damaged wiring harness section near the steering column. This was not a major repair, but required proper diagnostic equipment to pinpoint the exact location of the fault. The issue could have led to other electrical problems if left unaddressed. Before visiting a shop, check if the turn signal connector housing shows any signs of melting or discoloration. Also verify if other electrical components like power windows or central locking work normally, as they might share the same ground points. A qualified technician should perform a proper diagnostic scan, as these symptoms can also indicate issues with the body control module or central electronics unit.

Thanks for the detailed explanation about the irregular signal lamp behavior. I can confirm my power windows and central locking are working fine, but I noticed the rear turn indicators sometimes flash faster than the front ones. Will check the connector housing for damage as suggested. Did you keep track of the repair costs? And have you experienced any other electrical fault issues since the wiring harness was replaced? Just want to get an idea of potential costs and if this fix tends to be permanent. Flasher relay problems seem tricky to diagnose, so knowing if your repair held up would really help me decide how to proceed.

Finally got a chance to update on this. After bringing the car to a qualified mechanic, they found and fixed the defective turn signal lamp issue. The problem was traced to a faulty cable connection at one of the main plugs, similar to what I experienced with my Tiguan. The total repair cost came to 95€, which covered diagnostic testing and fixing the connection. Actually turned out cheaper than my original repair since they didnt need to replace any wiring harness sections. The automotive lighting system has worked flawlessly since the fix six months ago. No more erratic flashing or stuck signals. The mechanic mentioned these connector issues are fairly common and once properly repaired, they rarely cause problems again. For reference, the repair took about an hour and they tested all signal lamps thoroughly before returning the car. The flasher relay itself was working correctly, it was just responding to the poor connection, which made it seem like a relay problem initially. Based on both our experiences, these irregular signal issues typically point to connection problems rather than component failures. Getting it properly diagnosed saves both time and money in the long run.

Thanks everyone for the help. Just wanted to close this thread with my repair experience. Took the car to a new mechanic who ran a complete electrical fault diagnosis. The turn signal irregularity was caused by a corroded ground connection, not the flasher relay as I initially suspected. The mechanic found the issue quickly with proper testing equipment. Total cost was 160€, higher than expected but included a thorough check of the entire turn indicator system and cleaning of all relevant connection points. The lamp replacement wasnt necessary since the original bulbs were fine. The repair took about 2 hours. Been driving for a few weeks now and all signals work perfectly, no more irregular flashing or stuck indicators. The mechanic also showed me the corroded parts they cleaned, which helped understand why the problem occurred. Definitely worth getting it fixed properly rather than trying quick fixes. The thorough diagnostic approach saved me from replacing parts unnecessarily.