Hey everybody. I am working on a 2000 5FBCU25 36 Volt, with 21k hours and 11k miles. Last year I drove this thing normally, then it was parked outside due to bad battery.
We now installed new battery.
Keyswitch on, the display panel comes on. Horn works, but that's it. No movement, no steering, no lifting, and no codes. Code A7 pops up if I lift myself off the seat. 2 white great fuses in the back and 2 small tube fuses in the front are good.
Unable to enter the settings menu. The display takes the first password (display changes from "0" to "1"), but not the second one (changes back to "0").

Last week one time the lifting motor somehow turned on and all lift functions for a few minutes, but not after restart. If I have a helper push on the Lift contactor with a screwdriver, lifting functions start working.

I discovered 3 rat chewed wires. In the center right under the battery, in the low voltage harness, Green, Blue and Purple wires stick out about 3 inches. I do not see where they could have possibly been plugged in, there is nothing around. Could they be the reason?

I spent several hours unsuccessfully trying to find the wiring diagrams for this forklift. If anyone has electrical diagrams for this model, kindly share.

How do I troubleshoot this?