1990 Johnson Evinrude "ES" 9.9 thru 30 Service Manual, P/N 507871, Page 289Get this manual
Key Switch Check
Ohmmeter I]Q] 1Disconnect battery leads and leads at the key switch
2 With key switch in "OFFposition, connect continuity light or meter leads between key switchBATT" and "A" terminals Light or meter should not show continuity