How long do you have to return a car to the dealer?

There is no 'Cooling Off Period' or "3-Day Right-to-Rescind" for automobile purchases anywhere in the USA. The right of rescission only applies to contracts signed for goods or services when the contract is signed at your home. It does not apply to a usual place of business. It was designed to prevent people from being victimized by professional high pressure sales people who sell goods and services door to door and pressure people into signing contracts. When you go to a place of business, you always have the option of walking out. You can not walk out of a sales situation in your own home.

Once a vehicle is "delivered", it's your vehicle unless the dealership grants you a refund. A completed delivery involves going to the dealership, signing all the necessary paperwork, arranging payment either by a cash purchase or financing then driving the vehicle off the dealership's property. It is important to read the contracts you are signing and make certain you have a copy of every document. Never sign until you know all the figures and have a "We Owe" signed by the General Manager for any open or 'promised' items.

Exceptions: California dealerships must offer the customer an option to purchase a "3-day return policy". If the customers signs the waiver instead, then they do not get the ability to return the car. In addition, Carmax does offer a 5-day return policy, however that is not a law, it's a promotion they offer to their customers.

Read your contract. The contract binds the seller and the buyer to the terms provided in the contract.