The ignition switch in a motor vehicle is the main electrical component used by the operator to start, run and turn off the vehicle. The main purpose of the switch is to allow the operator to safely engage the ignition system and activate the electric starter. Replacement of the ignition switch becomes necessary when you have trouble turning on the electrical system, or if the starter fails to stop turning after the motor has started.
Locate and identify the pins on the back of the ignition switch, There should be four terminals marked “BATT” for Battery, “ST” for Start, “IGN” for Ignition, and “ACC” for Accessory. Some switches may use a different letter or number code, so check with the manufacturer of the switch to properly identify the terminals.