I had the same issue, drivers seat.
I never took the time to TS and find the problem. It first started flickering on and off various times and finally just stayed on. I'm sure my issue is in the connector or the line leading to it. Honestly, I got frustrated and made a chunk of wire with two spade connectors on it and jumpered the plug under the seat. It was laying on the floor under the stuff I carry under the seat. I simply unplugged it and replaced with my spade connector. I wear the seat belt all the time anyway so it was useless as tits on a boar anyway. #@$%!