yes richard, this is true, the sensors only interact to tell the position of the steering wheel. I realized after i made that post something else may be causing the issue. I remember once i dealt with a unit that had gone past it's stop point because the stop had broken and it wound up the hydraulic hoses around the steer unit and broke some fittings so it appeared to be turning around too far and was uncontrollable until i repaired the hoses, the stop and the sensors that had gotten damaged. Once i got that sorted out it did operate ok then.
Thanks for that reminder though :o)