What other loads are you putting on the machine when it flickers? How old is your machine and its battery?
Did you check and clean the positive/ground connections at the battery?
Check and clean the main chassis ground from battery.
A friend has a 17 700-4 deluxe. His has power steering flickers as well in the winter when using his snow plow. I told him to change the way he pushes snow, activating his plow while turning is too much load on his factory battery. I am in the middle of talking him into a full size battery under the seat to help this issue.