Customizing your car with Arduino is getting easier and easier, with plenty of examples online. After the MPGuino Community, different OBD and CAN shields, we welcome the JEEPuter:

The JEEPuter is a programmable push-button system for controlling things like ignition, GPS navigation system, CB radio, RF scanner, 110V inverter, external and internal lights, and garage lights too. The JEEPuter also has temperature and light sensors which can set the dash lights and internal lights on autopilot.  As a final touch, the Jeep’s ignition starts when you type a passcode instead of turning a key.  While the JEEPuter is specifically for the Jeep Wrangler, you can learn from the build and apply the techniques to your own car.

via [Hack’n’Mod] source [JEEPuter]