blows F19 fuse



2016 SS, Installed SC, Headers. (car ran) After tune/dyno. Airbag/TCS light (service) ON.
F19 10amp blown. If replaced, light goes out, but blows shortly after.
Inspected ALL harnesses close to headers, Nothing. (small loom melt on LH O2)
Tuner left No# 4 plug wire loose, ARCING on dyno (and deliveried) I fixed it.
I thought it was a header leak.
Could this have Back feed the system?? (mechanic 30 years) Sensors all on ML amps, HIGH ENERGY BACK FEED???