2005 Mitsubishi Outlander

Electrical problem
2005 Mitsubishi Outlander 4 cyl All Wheel Drive Automatic 73000k miles

Interior light in car do not come on when I turn off engine and remove key from ignition or open any door. Light bulbs are serviciable and I can switch on light with over head Dome light switch.

Car is within warranty but Mitsibushi does not want to fix it because remote starter on Car (after market) was installed by some one else.
Problem still exist even after disconnecting remote starter circuit therefore it is not remote starter that is causing fault.
any clue? Which unit control interior lights in car.