It's not a single easily accessible valve like a radiator petcock. The temperature control is managed by a blend door actuator within the HVAC system's housing located inside the dashboard. This actuator is controlled electronically or by cables connected to the controls you operate inside the van.
To find the issue if your temperature control is malfunctioning, you'd likely need to:
* Consult a repair manual specific to your year and model: This will give you diagrams and locations of components for your particular HVAC system.
* Look for the HVAC blower motor: The housing containing the blend door actuator is usually close to the blower motor, often under the dashboard. Access may require significant disassembly.
* Consider professional help: Unless you're experienced with automotive HVAC systems, attempting repairs yourself could be difficult and potentially lead to further damage.
In short, there's no single "temperature control valve" in the traditional sense. The temperature is regulated internally within the HVAC system, and diagnosing problems requires specialized knowledge and tools.
