Wire connections
56a = High beam
56b = Low beam
56 = High / Low switch on the dash board
31b = Headlight flasher switch
15 = Power from the battery

To replace 679337 Overdrive Relay
Wire connections:
15 and 56 = Power from the battery
56a = Overdrive and Overdrive light
31b = Overdrive Column Switch

This part replaces part no 688537, 688357, 688355, 679337.