[sangnoir]

> Wait what? Why is a headlight influenced by a turn signal

All cars with "Daylight Running Lights" (housed in the headlight assembly) turn them off for that side when the turn signal is active. I assumed this is to make the turn signal more obvious (as the change in brightness is more prominent).

[lightedman]

In many cars, the daytime running lights are also the headlights. Mine are in a 2013 Subaru Outback. However, they remain separate from my turn signals and do not deactivate when my signal activates.

For more modern vehicles, they have to turn off the LED/Laser-phosphor unit entirely because the lights design is too radiant and glaring for the turn signal to be seen. GMC and Ford big-ass trucks made within the last 5 years are an example.