This indicator light illuminates :
When you select "ECO" mode as drive mode.
WARNING
Do not watch the ECO indicator light while driving. This will distract you and may cause an accident that results in severe personal injury.
Hyundai Sonata LF 2014-2019 Service Manual: Injector Specifications
Specification
ItemSpecificationCoil Resistance (?)1.5 ± 0.075 [20°C(68°F)]
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Hyundai Sonata LF 2014-2019 Service Manual: Power Door Mirror Actuator Components and Components Location
Components
1. BSD Indicator2. Side repeater lamp3. Puddle lamp
...