How-to-guide - Dome light supervision

Dome Light Supervision

Dome light supervision is a feature found on many automotive security and remote entry systems. It's function is to illuminate the vehicles interior light for 30 or so, seconds after disarming or unlocking the vehicle, to "light  up" the interior for safety.

This feature typically is connected in the form of a single wire that provides a negative output to drive a relay connected  to the dome light, (also known as the courtesy light), wires.

Some vehicles will send a positive signal to do initiate the dome light or a negative signal. Most security systems will have the ability to accommodate either.

Pictured here are two types of door pin switches before insulation.

If any of the factory switches are damaged or you wish to add on to perhaps the trunk, many aftermarket security systems will include one or more pin switches with the system. If not, they can be purchased at most of your local car audio retailers or Radio Shack.

Locating the door pin switch

The best place to find the dome light wire is usually at the driver's door switch.

Older vehicles may have a mechanical switch in the door jamb that is easily seen by opening the door and looking in the door jamb.

Locating the dome light wire

You can find the dome light wire either at the switch, by removing it from the door jamb, or you may find it in the driver kick panel.

Connect the appropriate dome light supervision wire from the remote entry or security system to this dome light wire in the vehicles wiring harness as shown in the circuits below.

For vehicle specific wire color, location, and polarity (+) positive or (-) or negative) see :

Car stereo and security wiring

Wait now! I can not find my pin switch in the door jamb!

Never fear. Most newer vehicle pin switches are located inside the door and are built into the latching mechanical part of the door lock.

In this case, you can tap into the vehicles dome light wire either by removing door panel and locating the switch or the easer way is to simply find the door pin switch wire usually located at the driver kick panel.

So now you know the rest of the story, lets start the fun stuff!

Dome light illumination with negative output circuit

Dome light illumination with positive output circuit

Help!

If you are unable to identify the location of the doors switch, you can access this wire in either drivers or passengers side panel.

The side panels are the panel's located between the bottom of the windshield and the top of the windshield. 

If you were unable to identify the dome light wires at the panels you can always locate the wire at the dome light. Most dome lights are rather simple to remove.