not sure about "X" reg - but from 01 on .....
Side Lamps
When the lighting switch is turned to the side lamp position, current flows across the switch
(C0041) to fuse 16 and fuse 28 of the passenger compartment fuse box (C0587) on an R
wire. Fuse 16 (C0582) provides a feed to the following on RO wires:
The RH side lamp (C0011).
The RH front side marker lamp (C0916) (NAS vehicles only).
Fuse 16 (C0583) also provides a feed to the following on RO wires:
The RH tail lamp (C0125).
The RH rear side marker lamp (C0918) (NAS vehicles only).
The rear number plate lamp (C0138).
The trailer pick-up (C0499).
All are earthed on B wires except the trailer pick-up, which is earthed on a W then B wire.