CERTAIN WHEELCHAIR LIFT INTERLOCK MODULES, P/NO A-LOCK601-GD, INSTALLED AS ORIGINAL EQUIPMENT ON CERTAIN 2005-2007 CHEVROLET SCHOOL BUSES. WHEN THE VEHICLE BATTERY VOLTAGE DROPS TO 7.5 VOLTS, THE MODULE MAY GO TO A FAULT MODE AND NOT LOCK THE SHIFTER IN PARK WHICH FAILS TO CONFORM TO FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 403, PLATFORM LIFT SYSTEMS FOR MOTOR VEHICLES.