1994 Johnson/Evinrude "ER" 60 thru 70 outboards Service Manual, Page 120Get this manual
Blocking DiodeElectric Models If the 5.L.0Wwarning system is activated when warning horn receives no oil, low oil, or fuel vacuum signal, test engine harness blocking diode1Disconnect engine harness red connector2Disconnect temperature switch tan leadf313Calibrate ohmmeter on appropriate scaleConnect between tan lead and engine harness tan pin Note reading 4Reverse meter connections or press "polarity" buttonNote reading high reading in one direction and low reading in the other direction indicates the diode is good 5Replace engine harness blocking diode if your test results vary6Complete all circuits disconnected during this test {7