Adjusted the pot, doesn't seem to make any difference. Checked all wiring from pot/switches to the terminal block under the seat and everything checks out with 0.0 continuity. Stumped as to where to go from here, don't know where the cards are or even what they look like but the symptoms at the contacts remain the same both forward clicking/buzzing/chattering when trying to move straight ahead. Same symptoms on the reverse contacts when trying to move back and turning the wheel lock to either side causes just one contact to act up.

So with my limited electrical knowledge it would appear that the failure in the system is somewhere before the signal divides for forward/reverse/turn. I checked the common going to the forward/reverse selector switch which showed perfect 0.0 continuity terminal block to switch. Checked the signals from the accelerator pedal back to the terminal block and again clean signal from the pot and clean switch off/on/off on the 2 switches.

Looks to be deeper in the system than I have the ability to track down without schematics or a service manual.