Code FN - Relays Did Not Open at
Power Of
Code 61 - Mast Switch #1 Not
Crossed
Code 8L - Brake Feedback
Current Out-of-Range
Lets start with code fn which is related to k4 staying closed, B+ comes from the vehicle manager to the keyswitch, then too the relaycard and to the coil of the k4 relay, inspect the keyswitch for leakage when off, terminal 10 is the power input to the relay card from the keyswitch, you either have leakage across the keyswitch or still have issues with the fuse/relay card.
Mast switch #1, either a d-switch or a prox switch on the mast for when the carrage maxes out and the mast starts to stage, inspect it, but also maybe the encoder.
Brake feedback, does the brake release? measure the resistance of the coil, inspect for corrosion on the connectors/wires.
You should make a post in the technical section to see if someone can send you a manual, unfortinitly mine is paper so i cannot, that way you can have a wiring diagram in front of you, sometimes people have pdf manuals they are willing to send via e mail.