Cannot turn off or dim headlights when car is running

Welcome to 2CarPros.

I have some bad news. They can't be turned off in low light situations. The automatic headlamps and park lamps are designed to automatically illuminate when the ignition is RUN and the outside (ambient) light level is low, as in nighttime conditions. Light levels are detected by the ambient light sensor, a light sensitive transistor that varies its voltage signal to the Daytime Running Lamp (DRL) control module in response to changes to the ambient light level. When the DRL control module receives a low light signal from the ambient light sensor, it will then turn on the headlamps and park lamps and turn off the daytime running lamps.

When the ambient light sensor detects low light levels, the DRL control module turns OFF the daytime running lamps and turns on the headlamps and park lamps under the following conditions:
The ignition switch is in the RUN position.
The headlamp switch is OFF.
The park brake is OFF (released).

I wish I had a better answer, but that is how it's designed.

Let me know if you have other questions.

Take care,
Joe