No hydraulics after sitting for 6 months

I need help with my 1998 Cat 345BL. There's no hydraulic power at all. The red hydraulic light comes on like it normally does when cold starting, but the hydraulics won't engage and there's no attempt to move anything. What troubleshooting steps should I try?

What's the serial number on your machine?

4SS01066

Have you checked the hydraulic fluid level in the tank?

When you move the lever, do you feel or hear the operator presence safety solenoid click in? Are any of the hydraulic functions working at all—tracks, slew motor, anything?

Could be mice or rats chewing the harness.

Yup, opened up the cavity under the cab and found the wire to the hydraulic-lock solenoid was bitten clean in half. Something's made a nest in there too.

So it turns out some electronics got pretty chewed up while it was sitting, and I'm not even sure what half these parts are or how bad the damage really is. The thing is, I was able to run the excavator fine for a few hours, so it's working. How are you folks dealing with something like this?

A schematic would help. What's the serial number on it?

That's rough! The wires being chewed up right at the solenoid connectors makes it a tough spot. If the damage was a bit further back you might be able to splice them, but as it is I'm not sure how you'd repair them without swapping out those components. That's a pain.

I think you might already have an electrical schematic from when you were troubleshooting before, but if you need one just let me know.