Hi there,

I'd say, take the sled out of the car and have a quick look at the docking connector, make sure nothing's been yanked out. There should be a yellow wire with a black box connected to it. That's the fuse give that a look at as well. If you're confident opening your player then have a look at the docking connector on that. Plus the connectors to the mainboard.

Other than that, check your accessory fuses in the cars fusebox too. I wouldn't be too worried, if you can use it at home then I very much doubt there is anything seriously wrong.