[hOngsterr]

you can run the line without the sensor, the sensor is made to make you rev up when you're at full lock so you dont stall out. Also to flush the ps system, what you would have to do is, loosen one of the rack bolts that runs to the low power lines (there should be two, so obvi loosen the top one.) and have the front lifted up so you can turn the wheel side to side with ease, but when you're doing this make sure you have someone to watch over the level and dont let it drop so air doesnt get reintroduced into the system and when you fully flushed it, tighten up the bolt (dont know the correct term) and do a few more turns to be on the safe side.

This is what i think how you should do it, i been doing it like this no problem, unless someone actually knows and chimes in.