1998 Johnson Evinrude EC 5 thru 15 HP Four Stroke Service Manual, Page 332Get this manual
WATER TEMP Circuit 1Separate the connector between the engine harness and the temperature switch 2Using jumper wire, connect the engine harness tan lead to clean engine ground
3Turn the key switch to ON positionAfter the normal self-test sequence, the gauge WATER TEMP light should stay on If WATER TEMP light is not on, troubleshoot tan circuit for an open in the engine harness or the instrument harness4On engines, test both temperature switch tan circuits5To test the temperature switch itself, refer to Temperature Switch, Section 46Turn the key switch OFF and reconnect all circuits disconnected during these testsNO OIL Circuit