You may want to check around and underneath the seat to make sure there are no air leaks from fittings or hoses that may be "kinked" restricting airflow to the lumbar support, if in fact it is air operated.
Interestingly, a few months ago, our Driver's side foot rest extension failed to operate (extend/open), I did a cursory inspection and didn't find anything, but recently found a brass tab, just the tab, that you may find in a connector assembly laying on the floor near the fuel pedal. I haven't checked yet, but I'm thinking that may be my problem.
Keep us posted on what you may find.
John & Maria - Chester (furry kid)
2017 Cornerstone 45B - FMCA-#489135
2012 Scion XB - Pushing hard