Im new to the forum so bear with me I have ny grandpas 72 cub hydrostatic , nd maybe some other people have had the same problem , my vr died nd went nd bought a replacement nd realized my old one had ground , battery nd generator , the new one has battery , feild nd L what is L ??? B4 I realized it, I have the generator and battry lines hooked up nd put my lastcwire on l , I got ny tractor to start but then the next day my battery is stone dead , somebody please tell me whats L!!!???