279c low voltage in half of fusebox, no hydraulics

After lifting the cab and washing underneath, the parking brake will not release and the hydraulics won’t engage. Cat ET shows these codes: 2474-4, 2475-4, 2476-4, 2477-4 all relate to joystick voltage below normal. The upper half of the fusebox in the cab only reads about 3 volts at all the fuses. (No blown fuses) Same 3 volt reading on the back side and before the relay that supplies power to that box. The bottom half of that box reads 12v. Starts and runs, seat and armrest switches are working properly. The parking brake switch has power and works properly. All ground wire connections have been cleaned. I used compressed air to dry out all connectors and wiring that may have gotten wet. Battery is charged and good. Has anyone had similar issues or have suggestions? Cat 279c serial # MBT01291