Hi Miles,

Error 36 indicates that there is no zero position for the lift function, this means that the learned value for Zero/home of the lift lever potentiometer is not being met, it is possible that the lift potentiometer is worn thus the resistance is not what it was when it was 'taught in'
This symptom could also be caused by wear in the lift lever, if the lever now rests in a different position because of worn bushes for example,
Prove this by 'taking up the slack' on the lever when you start the truck up and see if it starts up without generating the error code.