Oil Pressure Switch Test
WARNING: This page is about a different car, the 1992 Honda Prelude, 1992 Honda Civic, and 1992 Honda Accord. However, it is still accessible from the selected car via links, so may be relevant.
Disconnect Yellow/Red wire from oil pressure switch. Use an ohmmeter to check continuity of oil pressure switch. With engine off, continuity should exist between oil pressure switch terminal and ground. With engine running, continuity should not exist. If switch fails to operate as described, check engine oil level and oil pump pressure.