Yamaha outboard wirring question

[Sugo]

I have a 2005 Yamaha OX66 200HP and was looking for a wiring tip.
The Yellow wire from 703 control box has 12 volts when the key is on but when you turn the key off the yellow wire still has 5 ish volts and holds. When I unplug the pink wire off the signal buzzer and re test the yellow wire has 12 volts with the key on and no voltage when key off. The residual voltage is coming from the power head via the pink alarm wire to the control box.
When I plug the pink wire back in to the signal buzzer in the 703 control box and turn the key on then off I measure 12 volts on the pink wire at the temp alarm sender on the power head. When the battery switch is turned off then back on, no voltage in the pink wire at the temp sender. I was under the impression that there should be no voltage in the pink wire, neutral until the sender grounds it, if the sending unit is triggered by high heat. Once I turn the key on then off again the 12 volts return the pink wire and does not dissipate until the battery switch is turned off resetting it. Any info on what I am missing? Should the yellow wire running the dash lights have 5 volts when the key is off?

 

[boscoe99]

For what purpose were you measuring voltage? Is there a problem?

The yellow wire is for key on power (12 volts) to the buzzer. And back to the engine as well.

The pink wire connected to the buzzer is grounded by the CDI to make the buzzer sound.

The pink wire from the thermoswitch to the CDI is grounded via the thermoswitch when the thermoswitch closes due to excessive temperature. This ground to the CDI lets the CDI know to ground the pink wire that runs to the buzzer. Different pink wires, different functions.

The yellow wire at the key switch having 5 volts could be a function of a switch that is not completely opening.

 

[Sugo]

Thanks for the reply and clarifications. As the wiring behind my dash was a mess I decided to install a new fuse panel and all new wiring. When I was confirming the yellow wire in the harness from the 703 box to the guauges was indeed 12v when key on (so it could be used for my external water pressure and trim gauge lights). I tested the yellow wire and confirmed 12v key on but still 5 volts when key off. This prompted my curiosity to dig in effort to understand the functionality. Maybe a fault in the key switch. When I disconnect the buzzer in the box (no voltage on yellow when key off. This is what started me looking to the motor for answers. Once I get everything back together I will retest, if I still have voltage on the yellow wire to the gauges. when the key is off I may replace the key switch to avoid any unnecessary battery drain, as I suspect the switch is the issue prompted by the info in your reply.