That's the standard configuration,for function 17.

Now,function 18 is the Power Steering Time Delay. If this is set from 0 to128,then the P/S will pickup on the seat switch closure,and will time out when the seat switch opens.

If function 18 is set between 129 to 255,the P/S will pickup on directional switch closure,and will time out when either directional switch opens.