Rear Defroster Relay

There should be continuity between terminals No. 3 and No. 4 when 12 volts is applied to terminal No. 1 with terminal No. 2 grounded. See Fig 1 . There should be no continuity when battery is disconnected.

Fig 1: Checking Rear Defroster Relay

Courtesy of AMERICAN HONDA MOTOR CO., INC.