Privately selling vehicles to dealership customers

The customers that come to the dealership intend purchasing cars directly from the dealership and not from you. You as an employee are required to sell vehicles to them from the dealership as you are employed for this reason. It is therefore incorrect for you to sell vehicles to the dealership customers after hours and make a profit for yourself. Yes, if you advertised a vehicle privately in your time and a customer (who also visits the dealership) contacted you directly after reading your advertisement, then there is no harm in selling the vehicle to him, with the proviso that your employment contract does not prevent you from doing so.