What is an idle kill switch on a Volvo tractor?

Depending on the year and model a kill switch will cut voltage to the injection pump solenoid causing the engine to stop.On older models a push-pull cable is linked from your cab to the injection pump cut off.On newer models a solenoid is used on the injection pump which could be deactivated by several kill switches , for example : ignition switch , a switch on the operators seat (to prevent accidents in case operator stands up while driving,ECM engine protection (sensors in engine kill pump to prevent engine damage).

Hope this helps