[roneby]

Why does JD do this??
Power Circuit Operating Conditions, Unswitched Circuits
Voltage must be present at the following components with the key switch in the OFF position:
These are needed
Battery Positive Terminal
Starting Motor Battery Terminal
Key Switch, Terminal B
Alternator, Terminal B
Why are all these hot with key off??
Glow Plug Relay, Terminal 30
Fuel Shutoff Relay, Terminal 30
Light Switch, Terminal B
Power Port, Center Terminal (if equipped)
Instrument Control Cluster, Terminal J1-B

Seems this could be a fire hazard with mice chewing on soy bean flavored wire.They chewed mine up.

 

[dixie460]

Why are all these hot with key off??

Glow Plug Relay, Terminal 30
GP's draw relatively high current so the relay is needed to switch them. As such it requires the power feed to be hot at all times. Switching it with the key directly would defeat the purpose of the relay.

Fuel Shutoff Relay, Terminal 30
Same explanation as above.

Light Switch, Terminal B
To enable leaving the lights on without the key. I'm glad JD did this, it's actually useful in certain situations. Also, at least on my 1025R, if you just want to check the hourmeter real quick you can turn the light switch on (any position) and the instrument panel will light up and show you the hours. No key required.

Power Port, Center Terminal (if equipped)
This is another handy feature. You can plug a battery maintainer into this port and it'll keep everything charged up. Also some of us like to let our phones charge and stuff even with the engine off. If the power port was switched with the key then neither of these things would be possible.

Instrument Control Cluster, Terminal J1-B
This is likely for memory purposes.

Seems this could be a fire hazard with mice chewing on soy bean flavored wire.They chewed mine up.
That stinks.... maybe get a cat? Or try one of those ultrasonic pest repellers?

If you think your tractor has a lot of live circuits, look at any car or truck made in the last several years. They just give the illusion of being "off" (i.e. engine shut down, screens and displays off) but many circuits are still powered.

 

[Pedals2Paddles]

Everything Dixie said. The power port and lights can be a matter of personal preference, but the overwhelming customer benefit is powered.

Everything has fuses. Just like any other piece of equipment and every automobile. I think you're overthinking this.

 

[MKE-1025r]

I’m curious as to how you know the wire tastes like soybeans.

 

[MarkEagleUSA]

I’m curious as to how you know the wire tastes like soybeans.

Most modern automotive wiring is made with soy-based insulation compounds. Rodents (and other critters) love it.

 

[BOBL]

They also love Decon, sticky traps, and the bottom of your foot.