Adding beacon lights is one of the easiest physical vehicle modifications.
This is where most people get started and learn the ins and outs of Giants Editor and XML editing.
To start out, open the vehicle in GE and switch to or create a new exterior camera.
Select the new camera and position yourself so that you have the view that you want of the vehicle.
If you do not create a new camera or use an existing edit camera, make sure you return to a centered above vehicle view before saving.
Create a "transform group".
The XML file will use this "transform group" to add a virtual light to the vehicle.
The transform group will appear in the Scenegraph.
Select it and then press CONTROL and X.
It will disappear momentarily.
Select the vehicle in the scenegraph and press CONTROL and V.
This will paste the new transform group in the vehicle's group and add it to the bottom.
Move the transform group to the location you want it. You may need to go in the game to check the placement and make corrections.
You can also change the name to anything you want. The name of the beacon light does not affect its performance.
Once you have the placement where you want it, save the vehicle, but don't close out of GE just yet.
Make sure the transform group you made for the beacon light is selected and locate the index path.
You can copy this or write it down.
In this case the Index Path is "0>15"
Open the vehicle's XML file.
You can add the scripting anywhere, but I like to keep it with the other lights.
You will need to add the following lines of code:
<beaconlights>
<beaconLight index="0>15" speed="0.015" filename="$data/shared/beaconLights/beaconLight02.i3d"/>
</beaconlights>
For general information-
This is the location of the beacon light that the game will virtually place on the vehicle in the location of the transform group you added. There are a few different lights you can select (01-07).
You should now be buy your modded vehicle in game and have a working beacon light. You can add additional beacon lights by adding additional lines of code between the <beaconLights> and </beaconLights>