Oil Pressure Switch Test

Remove the YEL/RED wire (A) from the engine oil pressure switch (B).

Fig 1: Removing YEL/Red Wire From Engine Oil Pressure Switch
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Check for continuity between the positive terminal (C) and the engine (ground). There should be continuity with the engine stopped. There should be no continuity with the engine running.