I would inform Hyundai that you will not turn the event into your insurance company because the vehicle is still under warranty AND you made no modifications or changes.
It's a "res ipsa loquitur
" situation - a rebuttable presumption or inference that the defendant (Hyundai) was negligent, which arises upon proof that the instrumentality or condition causing the injury was in the defendant's exclusive control and that the accident was one that ordinarily does not occur in the absence of
negligence or poor engineering or manufacturing on Hyundai's part.
If they won't agree, then you will have no alternative but to take the vehicle to have it inspected by a mechanic who can give their opinion after they examine the vehicle as to the cause or origination of the cause of the fire.
I would then have a mechanic determine the cause and then demand that Hyndai fix the vehicle.
The Arizona Lemon Law has a number of specific provisions. You should read the law and file a complaint with the Better Business Bureau AUTO LINE Program.
Here is the AZ lemon law:
The period covered by the Lemon Law is the term of the manufacturer’s warranty or two years or 24,000 miles, whichever is earlier. This covered period begins on the date of delivery of the vehicle to the consumer.
If there is a problem with the car that substantially impairs the use and value of the car and does not conform to the express warranty of the manufacturer, the consumer should report it to the manufacturer.
The report must be made during the covered period.
The manufacturer or its authorized dealers can repair or correct the defect, accept return of the car or replace the car with a new car.
There is a limit on the number of times a consumer must allow the manufacturer to repair the car and the amount of time the car can be out of service. If during the covered period, the manufacturer fails to successfully repair the defect after four attempts, or the car is out of service by reason of repair for a cumulative total of 30 or more calendar days, the manufacturer must accept return of the car or replace the car with a new car.
It's Hyundia's responsibility to determine the cause of the fire and repair the vehicle or they must accept return of the vehicle.