I have a 2004 Thomas safety liner with a rear engine . I haven't been here long but my supervisor said the switches are always failing . It has vandal locks on it so there are two switches . One for the warning buzzer and one for the vandel lock . I thought I saw somewhere Thomas had a retro kit to update this system . The last few days we go to get the bus and it will start .Park it go to start again and it won't start . Then the warning buzzer will go off and can't stop it . If you have some other ideas let me know . Thanks