Technical Description (Comment)
WARNING: This page is about a different car, the 2014 Mitsubishi Outlander. However, it is still accessible from the selected car via links, so may be relevant.
If the taillights illuminate, illumination signal is sent from the heater controller assembly (A/C-ECU) to the radio and CD player. This switches the illumination of the radio and CD player from day mode to night mode. If the mode is switched, the illumination signal line, the heater controller assembly (A/C-ECU) or the radio and CD player may be defective.