In a modern car, are the dome lights and headlights controlled by software or hardware?

[s355]

Does the dome light button soft (sends a signal to the car's OS to toggle the light) or hard (directly toggles the light)?

 

[kanewolf]

Does the dome light button soft (sends a signal to the car's OS to toggle the light) or hard (directly toggles the light)?

Depends on the vehicle. Most are probably hard because that is simpler. A basic light bulb (or LED) does not require dimming or other "fancy" things. Cars like the Cadillac that have color changeable interior lighting have to have some kind of smarts to save the preset and allow adjustment. That may be a stand-alone controller rather than a centralized computer.

 

[USAFRet]

Does the dome light button soft (sends a signal to the car's OS to toggle the light) or hard (directly toggles the light)?

Look up the wiring diagram. See what it says.

 

[lvt]

Headlights and dome light can be controlled by both manual switch and computer (ECU).

For example, headlights can turn on and off itself depending on road lighting condition. It also can be turned on/off manually.

 

[Lycogala]

Does the dome light button soft (sends a signal to the car's OS to toggle the light) or hard (directly toggles the light)?

What car? I have access to service info. I might be able to tell you how it works.