If want to turn it off, you have to go under settings and then it should come up and click turn off. If you dont have an account, then you wont be able to mature content at all. You must be a member to view those things.
There is normally a switch near the light (or sometimes on the dash) that sets the light to:
Always on
Always off
On when the door is open, off when it's shut.
If that switch is in the correct...
I think it's called "diesel effect". You need to check the combustion chambers for carbon deposits, also make sure to check ECU for error codes. You might have some ignition system problem.