Cutting the wires - what could go wrong?

[WorldClassAccident]

At each side of my bonnet I have 4 wires coming from the lights back into the car. I am guessing that each side there is a wire for Indication, Sidelight, Headlight and Main Beam.

To make my bonnets easy to swap I want to fit a single 4 way connector to each set of wires. I don't know which wire does what and they disappear inside bits of the bonnet so I cannot easily trace them.

I don't really need to know which wire does what to fit the connector for the existing bonnet. I just make sure that the 2 cut pieces for each wire are connected together afterwards. For the new bonnet I will need to know the order though.

My plan to identify which wire is which is as follows:

1) With the current bonnet in place check all the lights work.
2) Cut one wire and see what doesn't work. Label that wire accordingly
3) Repeat for the remaining wires until nothing works and all 4 wires are labelled
4) Fit connectors and wire them according to labels for existing bonnet
5) Check everything still works

rest

6) Fit wiring to new bonnet and label all the wires
7) Fit the connector with the labelled wires in the same order as the old ones
8) Fit the bonnet, connect up and check it all works

Anything wrong with the plan?