Riding Lawn Mowers

I just bought a Husqvarna YTH 21K46 ride mower and I can't get the lights to work. I've checked the hookup and the fuse and the bulbs. Where the solenoid is there is one white wire that is simply loose and not hooked up. However, it has a white and black wire already hooked up like it is supposed to. I know nothing about electrical stuff so was afraid to switch the two white wires out even though I thought perhaps this could be some sort of safety deal so they don't leave the lights on while it sits around waiting to be sold. The people where I bought it had no idea what I was talking about when I told them about this wire. It looks just like the other white wire in terms of the connecting piece on the end except it is a little thicker. Anyway, could someone tell me what this wire is and also throw some ideas my way for the lights. I can take it back and have it sent off but really don't want to do that since I just bought the thing and already had to go get a battery since the one in it didn't work. Love the mower though. It mows very well and I have a tough yard. I have added a picture where you can hopefully see the white wire that isn't hooked up. Thanks!