One of the rear wheels on my son's H2 Hummer (little tikes) will not move. The other rear wheel moves fine. The battery is charged. Everything is connected the right way. I purchased this toy at a yard sale and I don't have the owner's manual. I was told that the battery just needed charged. This is also the first motorized vehicle we have gotten for my son so I'm not familiar with these things. I would appreciate any advice or suggestions. Thanks Megan