Now remove the blocking diodes that are part of the original set up. I?ve done four of these locos, on the earlier three there was one diode at each end of the loco, but on the latest there were two per end.
With the ones on the chassis side you can just resolder the wires together.
On the body I decided to fit the inverse parallel diode for the top headlamp between the position of the old blocking diode and the top side of the relevant resistor. Ensure the diode is the opposite way round to the top headlamp led. You could use the original blocking diodes or new 1N4004 or similar, they?re only a matter of pennies each.
When you?ve checked the modifications reconnect the body and chassis wiring and test the lights before final reassembly of the loco.
Reassembly is pretty much the opposite of dismantling, just make sure that number one end of the body (it should be marked inside the cab roof) is at number one end of the chassis (usually marked on the frame and it should be the end with the driver fitted). Also remember there are three different sizes of screw, detailed earlier, and that the fuel tank only fits one way due to the spigot on the body.