1992 Johnson Evinrude "EN" 90 deg. Cross V Service Manual, P/N 508145, Page 149Get this manual
Blocking Diode If the S.L.DWwarning system is activated when warning horn receives no oil, low oil, or fuel vacuum signal, test engine harness blocking diode1Disconnect engine harness red connector2Disconnect both temperature switch tan leadsf31 3Calibrate ohmmeter on appropriate scaleConnect between either tan lead and engine harness tan pin Note reading4Reverse meter connections or press "polarity" buttonNote reading very high reading00in one direction and low reading in the other direction indicates diode is good5Replace engine harness blocking diode if your test results vary6Complete all circuits disconnected during this test DR2344