Ok.. so I'm trying to hook up an accessory to turn on when i hit the unlock button, off when i lock the doors. Basically, I want it to share the dome light's power so it follows the same routine. I tried hooking into the dome light fuse in the fuse box under the driver seat only to find out that the fuse is getting constant power. Where do I have to hook into? How can I get this to work the way I want it to?

 

The dome light has a negative trigger. You could use the domelight wire but need to use a relay. At that point you can make your relay provide a positive or negative to your accessory. The fuse box is just for providing power and protection to the circit.

 

Thank you. It definitely helps to know it's a negative circuit...but if I use the ground from the domelights wouldn't that mean that I wouldn't need a relay?

 

for my puddle lights on my 04 coupe, i hooked up the following:

bcm
pin 41 red/black +
pin 48 purple/red -

 

You need a relay to isolate what you are hooking up to do it right. If your accessory has an issue you don't want it sending a short or other voltage into the circit. And its the right way to do things. Just adding wires into new cars is not the right way. Added items should have their own fused power and use the cars wires as a trigger and not supply. The new vehicles that run on BCM systems (body control module) need to be treated with care. Its not like the old days when you could tape every wire and not worry about it.