Start by checking the vehicle's battery - it must be fully charged and able to handle a load. Once you verify this is good, then check for all cabling and connections to ensure they are all secure and corrosion free. If the problems persist, hands on testing by a trained professional will be needed for further direction.
RepairPal Certified shops can diagnose and repair your 2003 Ford Windstar. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.