1997 Johnson Evinrude "EU" Accessories Service Manual, P/N 507270, Page 201Get this manual
Trim Gauge Function
1Turn the engine key switch to ON position
rn 2.TRIM boat trim gauge should position, full trim-up when The indicate SNDR switch is in UP and indicate full tester
trim-down when tester switch is in DOWN position If gauge needle does not move, check instrument harness whitetan, black, and purple circuits for an open If gauge needle moved in one direction but not the other, replace trim gauge