Abstract: A vehicle thermal management system includes a cabin thermal loop, a battery thermal loop, a parallel valve assembly, and a controller. The cabin thermal loop includes a first chiller in fluid communication with a vehicle cabin. The battery thermal loop includes a second chiller in fluid communication with a high-voltage battery. The parallel valve assembly selectively links the cabin and battery thermal loops and includes a three-way valve and a conduit system arranged with one another to selectively link the first chiller and the second chiller to deliver cooling capacity to the battery. The controller is programmed to, responsive to detection of an available amount of cabin thermal loop cooling capacity exceeding a detected passenger vehicle cabin cooling capacity request, output a command to the parallel valve assembly to release the excess cooling capacity from the cabin thermal loop to cool the HV battery.