I looked on Brewer Sewing Supply, and their part number for your foot control is "FC-6605 Foot Control Kenmore 158 with 723 Cord." It's $33.90 retail, but you have to have a sewing machine business order it for you.
It's also available from Sewing Parts Online at this link:
https://www.sewingpartsonline.com/se...e+foot+control It's $34.99 right now.