Why does turn indicator on dash come on when headlights are turned on?

The turn indicator on the dashboard may illuminate when the headlights are turned on due to a malfunction in the vehicle's electrical system or a short circuit. This issue can cause a feedback loop where the circuits for the headlights and turn signals are inadvertently connected. Additionally, some vehicles have a feature that tests the turn signal circuit when the headlights are activated, leading to a momentary illumination. If this persists, it’s advisable to have the vehicle inspected by a qualified mechanic.