F5 displayed
possible causes are:
- Faulty wire connections?
- check the T1D, T2D, or T3D for failure
- the current limit may be set too low
- a failed D5D or D4D
- a failed driver board or a failed logics

now before you go and do all of the following i would make sure you check the usual things such as battery condition, all related fuses and contactors, check for any noticable physical damage such as burned wiring or contacts etc.

Then if you dont find the problem this is cat's suggestions below.....

key points to check are:
- wire 52 @ P12-5
- wire 37 @ P12-6
- emitter buss bar of drive power transistors
- wire 31 and 32 @ resistor R312
- wire 36 @ T1D, T2D, and T3D
- wire 34 from driver board to pos heatsink
- wire 1 from dirver board to neg heatsink
- wire 42 from logics P2-8 to current sensor
- wire 85 from logics P2-6 to current sensor
- current sensor connector to neg heatsink

I know having a wiring shematic or diagram would be helpful and in most cases there is one pasted to the rear door at the control panel.