why would we know anything about $19.99 walmart cars simply off a crappy connector pic???
Get a $4.99 multimeter probe these connections and figure out where the + and - are... chances are most reds are pluses and blacks minuses, but it could very well not be the case... but these things could work in parallel and you could toast it all first time you plug it in, maybe there's a reason they aren't cabled together in the first place... if you start modding electronic stuff, you'd either better know what you're doing or simply leave it as is...
good luck
Paul