How to Activate Empty Button in Volvo Dome Light

You can easily activate empty button in your Volvos dome light and use it with garage door opener, aftermarket immobilizer or any other gadget.

Enabling is easy. All you need is flat screwdriver, nail file, sharp blade and reset button switch from old computer case.

Step 1: Disassemble

1. Remove dome light.
2. Unhook plastic microphone dummy.
3. Unplug the buttons module.
4. Pry the frame and remove buttons module from the car.
5. Remove 3 torx screw from the module.
6. Remove the empty button.

Step 2: Customize

1. Use nail file and sharp blade to remove button limiters that prevent the button from moving in the module.
2. Make sure that the button moves freely and without any restrictions.
3. Use nail file to modify module body so additional wires won't be squeezed when the module assembled.
4. Cover existing circuit with isolating tape (or neoprene in my case) to prevent short circuit.

Step 3: The Switch

Depending on what kind of switch you are using you have to think of your own way to place it in the module. I've added a piece of rubber tube for additional support for the switch. Just to make sure that it didn't move deeper inside module.

Notice that the switch should at all time touch the button to prevent it from rattling.

Step 4: The Remote (or Other Device)

Depending on your garage door opener, you have to find a way on how to wire it.

1. Disassemble the remote.
2. Locate the switch and check if the pins are NO or NC (normally open / normally close) - this have to the switch inside your car. Most remotes will have NO switches that short the circuit when button pressed.
3. Solder two wires on each pin of the original switch.
4. Customize remote body so you can assemble it without breaking the wires.
5. Connect wires from the remote to the button inside your car.