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Tutorial: How to wire up map lights


Jun 28, 2014
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Here is a quick and simple tutorial on how to wire map lights from a Vectra or Omega in your Astra mk3.

1. Requirements

-Phillips Screwdriver (and a Flathead for prying off the original interior light)
-Wire connectors:
  • 2 x Female (shielded preferred)
  • 1 x Male
  • 1 x Forked
-Wiring (a strand of 6 inches long)

2. Understanding the system.

It is important to know that the interior light in the mk3 is turned on and off by a switch that toggles the ground (negative) black wire. NOT the positive red wire!
Thus in order for the map lights to work, you need to bypass the door switches that turn off the light once the doors are closed.
Remember how the light toggled by the negative wire? That means there is a permanent live 12v wire going to the light.

All we need to do is add a permanent ground (Negative) to the map lights and then they work independently from the door mechanism.
In a vehicle, the entire metal body of the car is our ground (Negative). So it's as simple as finding a bare screw and hooking a wire to it.

3. Tutorial

Your map lights will always come with 4 Terminals on it:

The position of these Terminals may differ from type of map lights, but the pin-out remains the same on ALL of them.

1. Narrowest flat Terminal: Maplight Live.

2. Medium flat Terminal: Door switched Ground.

3. Widest flat Terminal: Permanent Live. You will need to bridge this to the narrowest flat Terminal.

4. Curled Terminal: Permanent Ground. Connect this to a screw that you'll find in the housing of your car's light holder.



-Start by prying out the old interior light, Then disconnect the wires and store the original housing somewhere safe.

-locate the red positive wire and clip off it's original connector. Then leave it as is for now.

-Make yourself a 3 inch long wire Assemble a female wire connector on one end.

-Grab the red positive wire coming out the roof, wrap it together with the bare end of your new 3 inch wire and then assemble another female connector on the merged wire.

-slide the Merged wire connector on the Widest flat Terminal.

-slide the other end of that 3 inch wire on the Narrowest flat Terminal.

Connect the black ground wire coming out of your interior housing to the Medium flat Terminal.

Make a 5 inch wire, with a forked connector on one end and a flat connector on the other. then connect that forked end with a screw located inside the roof housing,
then connect the flat end to the Curled Terminal

You should now have something like this:

After you done that, the map lights should work perfectly, be sure to test it out before stuffing it back into the roof housing. You don't want to stress those old plastic clips too often.I hope this helps some of you who struggled with figuring it out :).

extra notes:
-Will have a sketch of the wiring up later today.
-The Terminal's locations differ on the type of map lights, but their shapes will remain the same and so will each shape's purpose
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