The idea that steam bending wood introduces moisture to the wood keeps re-appearing. I know this is counter-intuitive, but this needs to get solved.
Steam bending actually dries out the wood and lowers the moisture content due to the high heat!
You DO NOT want to put an already dry piece of steam bent wood into a scorching hot car, lowering the moisture content even more. Instead, place it at a normal room temperature so the wood can gain some moisture again. One day of stabilizing might be enough, but two days will be better. More won't hurt, obviously.