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The first thing you'll want to do is make sure all of your tires are set at 36 PSI when cold. If the light still stays on after that then the next step would be to use a capable scan tool to see what fault codes are stored regarding the tire pressure monitoring system. If the warning stays on but the tire pressures are ok then it's likely that you have one or more sensors that are bad or have low batteries. The batteries in the sensors do have a finite life and the sensors will need replacement when the batteries die.
The power door locks on your van are controlled directly by the body control module (BCM), so there aren't any fuses in the circuits.
The BCM constantly monitors the current draw on the left and right lock and unlock output circuits, and when the draw goes over a threshold it will disable the locks to preserve itself from damage.
The original BCM software was a little sensitive to this and could disable the locks prematurely. The software was rewritten to be more fault tolerant and not disable the locks prematurely.
As a temporary fix you can either disconnect your battery or remove the IOD fuse for a couple minutes. This will clear the fault codes from the BCM and restore the locks again. The permanent fix is to have the BCM software reprogrammed with the revised software. This will need to be done at your dealer and will take about a half hour of their time.