A vehicle equipped with air ride rear suspension will not lower when a load is removed from the trunk. What could be the cause?

The scenario describes a situation where the air ride rear suspension does not drop after removing weight from the trunk, which typically indicates that the system isn't able to regulate the air pressure correctly. In this case, a plugged air supply solenoid can indeed prevent air from being supplied to the suspension system, which would result in the failure to lower the suspension as intended.

When the trunk load is removed, the suspension should automatically lower due to a decrease in demand for support. If the air supply solenoid is blocked or malfunctioning, it won't allow the air to escape or be dispersed effectively, thus not enabling the system to respond to the changed load conditions. As a result, the rear suspension remains in its loaded position rather than adjusting itself properly.

While other components like the air compressor, air compressor relay, and air vent solenoid play important roles in the operation of the air ride suspension, they do not explain the specific failure to lower observed in this case as directly as a plugged supply solenoid does. The compressor's performance or relay functionality affects the overall system, but if there's a blockage in the air supply line itself, the system cannot communicate effectively with those components to function properly when load conditions change.