Van conversions is recalling 52 MY 2004-2007 Ford E-150, E-250 E-350 and MY 2006 GM savanna 3500 vans built on Ford and GM chassis and equipped with ricon platform style wheelchair lifts. These lifts fail to comply with the requirements of Federal Motor Vehicle Safety Standard no. 403, "platform lift system accessible for motor vehicles, " the anti-stow interlock may not detect the presence of a wheelchair or mobility aid user. The pressure sensing switch that detects the presence of weight on the platform was not adjusted to the necessary sensitivity level. The lift could stow even though someone or something is still on the lift.