School Bus Vandalock System No Crank Troubleshooting

imported_John Whelan - May 2, 2018
I had to post this and share the flaws in the Vandalock systems on both Thomas and international school buses that we have experienced in our fleet. First of all what is the Vandalock all about? The main purpose is to stop bus theft if someone happened to get hold of the ignition key and also vandalism to lock out the entrances. On the International buses there is a separate key that energizes the vandalock from an outside switch that disables cranking and in the newer buses secures the entrance door. The video shows an older system that just has the actuator arm.

international is the only bus that has this system wired in to the entrance door which has given us the most trouble. I demonstrated how the lever drops down and activates the vandalock and next time the bus ignition is used to start the vehicle there will be no start at all. Above the entrance door is the first check I advise the drivers to do. This is when the alarm is on and the starter does not engage.

I've talked drivers through this situation many times and it's slowly get ingrained in to everybody's head. The first step on all International buses is to look inside the small compartment above the entrance doors. The lever must activate the small micro switch which causes the start disable circuit to open and allow starting.

Thomas buses have vandalock as well at the rear door on the conventional buses and the rear emergency exit and side door emergency exit on the pusher rear engine models. The rear door latch on the Thomas conventional bus is a different design from International but works on the same principle.

The rule of thumb first step when a school bus does not start with alarm on is to check to see that the emergency exits are operational before going to the next step to troubleshoot the problem. Many time over the years the latch on a door has been accidentally closed or rough road has forced the lever on the entrance door mechanisms to drop down causing the starting operation to deactivate.

I agree with this design to stop theft or vandalism but with that comes the possibility of a no start. The vandalock can be tested during a service for proper operation and adjusted to avoid a failure on the road. Since dealing with this we have become wiser and incidents have dropped to a minimum.
School Bus
no crank
no start