Torque wrench is absolutely correct. But I have seen children drop coins in the cigarette lighter socket and or the lighter socket to fail and short due to after market accessories like GPS and radar detectors.
You might have a short in the element part of the lighter itself or socket. But I need to ask a question do you use the lighter or are you using the socket to power a cell phone chager, GPS or similar equipment? If so, it might just be a short in the power cord to your equipment. I have seen this problem many times from cell phone car chargers. try a different cord if this is the case.