Two thieves spotted an FDNY supervisor’s car idling outside of a Bronx hospital Saturday and decided to take a spin, police said.

The suspects climbed into the red GMC Sierra truck outside Jacobi Medical Center at around 10 p.m. and drove away, police said.

Police tracked the men using the car’s GPS system to the Soundview Family Housing at Metcalf and Seward avenues, about five miles away from the hospital.

The suspects were sitting inside of the FDNY vehicle when authorities found and arrested them, police said.

Joshua Gicead, 31, and Jorge Santiago, 54, were both charged with grand larceny, petty larceny and unauthorized use of a vehicle.

Santiago, who was found at the driver’s seat, was also charged with possession of stolen property for the FDNY truck utilized by an EMS lieutenant and paramedic, investigators said.