Signature line is in the use control panel. I haven't done it lately, so don't remember the details. I suggest you measure the rest voltage of the 12 volt battery, by releasing the hood latch and then leaving the car off for 15-30 minutes, then opening the hood (but no doors) and checking voltage with a multimeter. Anything over 12.6 volts is fine, 12.5-12.6 is marginal, and anything below that indicates a very low battery. Many of us trickle charge our 2013's battery with a battery maintainer when plugged in. I added a hardwired connection through the charging port compartment. You especially want to avoid leaving the car plugged in but not charging for more than an hour or two, unless you know the 12 volt battery is above 12.6 volts or a maintainer is connected. The battery will eventually get drained otherwise.
2013 "Brilliant Silver" SV with Premium and no QC, a 2009 Vectrix VX-1 W/18 Leaf modules, and 3 EZIP E-bicycles.
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.