7Y3918 7Y-3918;. Fits Caterpillar CAT 307 307B 307C 308C 311 311C 312 312BL 313B 314C 315 315BL 317 317BLN 318B 320 E320 E320B 320L 320N 321C 325C. Ignition switch. Safety switch. Combination light switch.