Poulan Pro 42" will only start with head light switch on?

This is so strange. I have a 2010 Poulan Pro that the head lights will not come on. While flipping the switch back and forth, I left the switch in the off position. When I tried to start the mower, nothing. Checked battery and it had plenty of juice. Turned light switch to the on position and it starts. Crazy! Do you think that I have a bad ground or is this a safty feature?