To find the relevant components:
* Vacuum Control Module (VCM): This is the brain of the operation. It's likely located somewhere under the dash, possibly near the HVAC blower motor or behind the glove box. It's a small, often black, box with multiple vacuum lines connected. This is the primary component to check if your vents aren't working correctly.
* Vacuum Actuators: These are small diaphragm-operated devices that open and close the vents. They're connected to the VCM via vacuum lines and are located within the dash itself, controlling the direction and flow of air. Finding these requires removing parts of the dash trim.
You'll need a vacuum gauge or a hand-held vacuum pump to test the system. Troubleshooting involves checking the vacuum lines for leaks, ensuring the VCM is working properly (by applying vacuum to its inputs and checking the actuator responses), and inspecting the actuators themselves for proper function. A wiring diagram for your specific van will be extremely helpful in tracing the vacuum lines.
Important Note: Working on your vehicle's HVAC system can be complex. If you're not comfortable working on automotive systems, it's recommended to take your van to a qualified mechanic for diagnosis and repair. Incorrectly diagnosing or repairing vacuum leaks can lead to further damage or safety hazards.
