Dome light wiring question, please help.
04-13-2007, 07:13 PM
#1
Staging Lane
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Join Date: Apr 2005
Location: Royal Oak, MI
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Dome light wiring question, please help. First of all, I searched, no luck. I am trying to wire up CCFL's to come on when the dome light comes on, but I'm confused about the wiring. Under the A-pillar there are three wires for the dome light, black, blue/white, and white.
Black is obviously the ground, blue/white is always hot, and white is hot when the dome is OFF. Is there a wire somewhere else that is hot when the dome is on, or am I missing something. wtf??? Any ideas will help, thanks.
Black is obviously the ground, blue/white is always hot, and white is hot when the dome is OFF. Is there a wire somewhere else that is hot when the dome is on, or am I missing something. wtf??? Any ideas will help, thanks.
04-15-2007, 11:11 AM
#2
You are correct - the black wire is ground - but it's only there so that the map lights can be turned on with the switches in the mirror. The courtesy lights never use that ground. The dark blue with white wire is constant power until a few minutes after the car is shut off, then the BCM turns off the power as part of the battery saver feature. The white wire is actually the ground for the courtesy lights. The BCM reduces available ground on that wire (increases positive voltage) to provide the theater dimming effect of the courtesy lights. It's that white wire that really controls when the lights are on or off.
You'll have to wire your CCFLs for power from the dark blue with white wire and ground through the white wire - there isn't any power wire you can use that is only on when the courtesy lights are on.
You'll have to wire your CCFLs for power from the dark blue with white wire and ground through the white wire - there isn't any power wire you can use that is only on when the courtesy lights are on.
