Left Turn Signal Stops Working and Warning Light Appears 5-10 Minutes After Starting Engine

[tunak]

Hello everyone.
I drive a 2021 Normal First Edition in Korea and am experiencing a strange electrical issue.

Symptoms:
1. When the vehicle is cold (Key On or immediately after starting the engine), the turn signal works perfectly fine without any problems.

2. However, after driving for about 5 to 10 minutes, a 'Light/Bulb Defect' warning light comes on in the dashboard.

3. Once the warning light is on, the front left turn signal stops working (which is likely the reason for the warning).
Questions:
Why does it stop working after I start driving?
Has anyone else experienced this symptom with a stock turn signal?
Any suggestions for possible causes or your opinions would be a great help!
Thank you.

 

[Petrus]

Apart from the obvious; a dodgy LED, I would next expect the battery. If the battery is a on its last legs all sorts of weird faults can pop up.