Yamaha Tach rigging question

[captpn]

Hi,
Im repowering my flats skiff...so i bought a cherry 2004 yam 90 2-stroke. it came with everything, harness, binnacle, key switch, kill switch and analog tach. Heres the question.
It all makes sence on wireing, but on the tach(analog only, no trim/oil stuff) the 3 wires connect to the harness fine, but the tach light (blue/black i think) have nowhere to hook-up to.

Is this normal for Yamaha? or do they want me to rig it to the running lights? i just thought it would be part of the harness when the key is on.

Will i get a buzzer if the oil level is low with this rigging setup?

First post here...looks like a helpful forum.

[boats.net]

If you are using the Yamaha gauge wire harness(one with inline fuse on yellow wire) then you can do it one of 2 ways. In the middle of gauge harness there is a short blue wire and a yellow wire. If you want backlight in gauge to come on when turn ignition key on connect yellow and blue wire togather. If you want the backlight to come with boat lights then connect blue wire to nav light side of light switch.