Merced County sheriff's deputies said the incident was discovered on the afternoon of May 15 outside a home off Beachwood Drive near Lobo Avenue in Merced. A Child Protective Services worker made the discovery while conducting a follow-up visit related to previous allegations of neglect.
Investigators said the employee found the child inside the vehicle, appearing to be sweating profusely and nearly unconscious.
The child was taken for medical care and has since been placed with a family member.
Elizabeth Arms was arrested and booked into the Merced County jail.
An investigation remains ongoing.