Yamaha tachometers on Explorer 275 TXRD 225’s not working (both)

[MV2]

Both of my tachometers won’t come on when key turn. Speed and fuel management gauges come on and are on same power. Is there a fuse on the ground?  I can’t find it!!  Is it at the engine fuses, or inline somewhere?

Just had to replace all the engines fuses, and may have missed on.

[MV2]

Still not been back on water, but soon to test. Do the tachometers need to re-sync or reset?  Have not had engines running yet. Dumb question, do they come on
Without the engine running?

[RickK]

The tachs will power on and light up but no readings until the engines are running.

[MV2]

Thanks Rick, they don’t light up at all, but I cannot find a fuse to test/replace. Had to replace fuses at motors.

[boatnamesue]

Tach receives power from yellow accessory feed and grounds with black.  The yellow does have a fuse on the harness between the throttle and tach.  No coincidence both tachs are out yet all your other gauges are working.  Likely a bad tach ground or blown fuse.  Good luck.