You might find this annoying, but in actuality, the trunk light of your Toyota Camry will automatically activate when you open the trunk. Unlike the other interior lights of your vehicle, you cannot set the trunk light to stay off when open.
If the trunk light is not working correctly, you should ensure the latch that turns the light off and on is free of dirt and debris. If this doesn’t solve the problem, an electrical issue is the likely culprit. Make sure to have a professional look it over.