2003 Polaris ATV Trail Boss 330 Factory Service Manual, Page 190Get this manual
ELECTRICAL
ELECTRONIC THROTTLE CONTROL (ETC) SWITCH (COMPOSITE THROTTLE HOUSING)
The Electronic Throttle Control (ETC) system is designed to stop the engine of an ATV in the event of mechanical problem with the throttle mechanismThe ETC switch is mounted independently of the throttle actuator lever inside the throttle block assemblyThis is normally closed switch, and is held in the open position (contacts are separated as shown in Illustration 1) by throttle cable tensionThe contacts are "open" in normal operation regardless of throttle lever positionIn the event of mechanical problem in the throttle mechanism (cable tension is lost), the switch contacts close, connecting the CDI black wire to ground, preventing ignition sparkThis is the same as turning the key or engine stop switch "OFF"
Test the ETC switch at the harness connectorNOTE: Adjust throttle cable freeplay (ETC switch) and make sure throttle mechanism is functioning properly before testing the switchRefer to Maintenance Chapter for cable adjustment procedure