Hello all!

I have a 2013 Cadillac Luxury model ATS 3.6L RWD.  I bought this car recently and have something strange going on with the ambient light/auto headlight function.  I notice that there is an indicator on the instrument cluster that indicates when the headlights are on.  The headlights stay on, no matter what the light conditions are, however, the headlight indicator on the instrument cluster turns off when in daylight, telling me that the light sensor likely isn't the issue.  (When the headlight indicator on the dash turns off, I get out of the car and can see the headlights are still on.)  The computer thinks the lights are off, but they aren't being switched off.  What is a good first step in troubleshooting this further?  Could it be a relay? 

Scotty would likely say "Don't buy a car with one of these stupid headlight sensors in the first place!"  Hahaha.  I can manually turn them off every time I start the car, but I'm hoping to figure out what the issue is.  Those halogens burn hot, and there's no reason to be driving around all of the time with them on.  I rarely drive at night. 

Thanks in advance!