WARNING: This page is about a different car, the 2016 RAM 3500 HD and 2016 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.
Possible Causes
HEADLAMP SWITCH MUX CIRCUIT SHORTED TO GROUND
HEADLAMP SWITCH MUX CIRCUIT SHORTED TO THE HEADLAMP SWITCH MUX RETURN CIRCUIT