How to sync with my dome lights..??
Thread Starter
On The Tree
Joined: May 2013
Posts: 136
Likes: 15
From: Dirty D, CA
How to sync with my dome lights..?? I bought stainless steel door sills with indiglo Z28 logos in them. I want to wire them to where they are on the same timer as the courtesy dome lights. I went into the fuse for the courtesy lights and wrapped it, but when the dome lights faded out, the sills stayed illuminated. Is there a sort of intelligent box or timer for the lights I need to get to? Any info would be much appreciated.
Joined: Nov 2003
Posts: 11,328
Likes: 346
From: Jacksonville, FL (originally from Toronto Canada)
This has been discussed a number of times but you would have to know that they are called courtesy lights for a search to be successful, so here you go...
The courtesy lights (dome light and mirror lights) are controlled by the Body Control Module (BCM). It is a black box about the size of a paperback book mounted under the dash on the right side behind the glovebox. It provides constant power to the lights until about 10 minutes after the ignition is shut off (to protect the battery if a door is left open). The BCM controls when the lights are on by varying the ground side of the circuit. That allows it to create the theater dimming effect as the lights are turning off by gradually increasing the resistance in the ground circuit until the lights are off.
Constant power is supplied because the mirror lights serve dual duty as map lights. The map light switches in the mirror simply provide a chassis ground that bypasses the BCM's variable ground so the lights will turn on at any time. That's why the COURTESY fuse has constant power.
To make any additional lights work the same as the courtesy lights, you have to tap into both the power and ground sides of the courtesy light circuit. You can do this at any one of the lights or at the BCM itself. Power is on the dark blue with white wire and the variable ground is on the plain white wire. If you connect at the BCM, the dark blue with white wire is in the black 6-pin connector (there is also a plain dark blue wire in that connector) and the white wire is in a corner of the blue 32-pin connector (there are several other wires with white in that connector but it is the only plain white with no stripe).
The courtesy lights (dome light and mirror lights) are controlled by the Body Control Module (BCM). It is a black box about the size of a paperback book mounted under the dash on the right side behind the glovebox. It provides constant power to the lights until about 10 minutes after the ignition is shut off (to protect the battery if a door is left open). The BCM controls when the lights are on by varying the ground side of the circuit. That allows it to create the theater dimming effect as the lights are turning off by gradually increasing the resistance in the ground circuit until the lights are off.
Constant power is supplied because the mirror lights serve dual duty as map lights. The map light switches in the mirror simply provide a chassis ground that bypasses the BCM's variable ground so the lights will turn on at any time. That's why the COURTESY fuse has constant power.
To make any additional lights work the same as the courtesy lights, you have to tap into both the power and ground sides of the courtesy light circuit. You can do this at any one of the lights or at the BCM itself. Power is on the dark blue with white wire and the variable ground is on the plain white wire. If you connect at the BCM, the dark blue with white wire is in the black 6-pin connector (there is also a plain dark blue wire in that connector) and the white wire is in a corner of the blue 32-pin connector (there are several other wires with white in that connector but it is the only plain white with no stripe).
