Why do my car's tail lights stay on even when the switch is turned off. on 1996 Nissan 200SX

My car battery died, I charged it up, but then i noticed why, it was because my car's tail lights had stayed on for hours, so why would they stay on even when the switch is turned off?

Get Your Car Fixed at a RepairPal Certified Shop.
We certify shops based on expertise, quality work, and verified customer reviews
1 answer
I think the first thing you need a scan tool to diagnose the code, and I know a tool is helpful for nissan, hope help. or you can take your car to the nissan dealer to read out the code, and then they will tell you how to do next.
http://www.chinasinoy.com/wholesale/nissan-consult-3-iii-software-professional-diagnostic-tool.html