Taillight Control Relay

Check that there is continuity between terminal Nos. 1 and 2. See Fig 1 and Fig 2 .
Check that there is no continuity between terminal Nos. 2 and 3.
If continuity is not as specified, replace the relay.

Fig 1: Identifying Taillight Control Relay Terminals

Fig 2: Testing Taillight Control Relay Continuity