Problem with reverse lamps

The (still active) code: mid 216 psid 8 fm 5.fault revese light.
I had problem with xy shifter and replaced it together with new harness.Mechanic who was working on it called me and told me somebody before for some reason didn't connect harness like suposssed to be,they run single wire from fuse box baypassing connection on harness for reverse light.He first connected harness like it supossed to be and reverse light didn't work and that code flashed.After he connected it like they did reverse light works but I still have that active fault code. Before installing new harness everything worked,no fault codes.What's best thing to do?

 

where is those fuse located