My rental car has no heat. What should I do?

Take it back, they should switch you out.

Go to the office where you've rented your vehicle. They will replace it for a different car.

Take it back and ask for a replacement

Call them; once my rental had no way to lock the vehicle! So I simply gave them a call...squeaky wheel gets the attention, as the saying goes🙄

Just wait for the car to warm up. Then turn the Aircon on and adjust the temperature into the red zone or heater zone.

Call the 1-800 number given by them. They should be able to switch your car.