project utilizing dimmer wire

Printed From: the12volt.com
Forum Name: Lights, Neon, LEDs, HIDs
Forum Discription: Under Car Lighting, Strobe Lights, Fog Lights, Headlights, HIDs, DRL, Tail Lights, Brake Lights, Dashboard Lights, WigWag, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=97560
Printed Date: July 21, 2025 at 11:28 AM

Topic: project utilizing dimmer wire

Posted By: focusedenergy
Subject: project utilizing dimmer wire
Date Posted: September 30, 2007 at 6:35 PM

First off, here's my car:
2006 Ford Focus ZX4 SE

I've got an idea for a lighting project but I'm not exactly sure how to accomplish it. I plan on replacing my stock dome light with CCFL's. In addition I also want to wire in footwell and courtesy lighting to come on with the dome light. The stock dome light is on a dimmer controlled ground. However, my idea is to have my UV CCFL's "fade in" when the dome light fades out, and vice versa. I believe I have seen a topic on another forum stating someone who accidentally made that happen, but I could have read that wrong. So my question remains. Is there any way to have different sets of lights alternate using the dimmer controlled ground, and how would I go about it? Will a relay need to be involved in this as well? Thanks.

Replies:

Posted By: ice32
Date Posted: October 03, 2007 at 8:27 AM

i just installed some CCFL into my car that i hooked up to the dome light and switches, By the sounds of things you want the same setup i used

posted_image

I used 12v diodes coz thats all i had lying around and they seemed to work and i switched the 12v as i used a hot 12v wire, so just in case i need to turn off the 12v i can.

I'll assume that your ground gets weaker causing it to fade, If thats not the case and its a positive wire that causes the fade effect replace the 12v wire in my picture with the dimming 12v power using the setup from this thread

If anyone wants to correct anything I've said please do so.

P.S Im not sure CCFL will fade, I'm pretty sure they just start going out

Posted By: ice32
Date Posted: October 03, 2007 at 8:29 AM

owh and of course, if all you want is them on when the dome light comes on, ignore the switches in that pic.

P.s its more then likely the 12v that causes the dim effect.

(these forums really need a "edit" button)

Posted By: the12volt
Date Posted: October 03, 2007 at 12:17 PM

As stated below the form: Note: Rookie members can not edit or delete their posts. Standard members may edit their posts if it is the last in the thread, and upload images....

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posted_image

the12volt • Support the12volt.com

Posted By: ice32
Date Posted: October 03, 2007 at 10:47 PM

yeh, just saw that, whats the post limit for standard member?

Posted By: ice32
Date Posted: October 03, 2007 at 10:49 PM

dw, turns out if i read fine print its all there

Posted By: focusedenergy
Date Posted: October 11, 2007 at 2:03 AM

I've not tried out the project yet.... in other forums there has been posts stating fading on a CCFL transformer will damage it. I may try LED's instead.
Is this true?

Posted By: fugitivealien
Date Posted: October 31, 2007 at 6:10 AM

I have a 2001 PT cruiser that has a fading dome light that i'd also like to wire in my underbody lighting.

I'm not concerned about the fade, just that when the dome is on the lights underneath come on. The control box has it's own seitch for the lights.

I can take the wire from the overhead light to the power of the lights, and put a diode on it's ground only, i'm not trying to get into the ground of the door system if possible. I'm also not wanting it to change the interior light's functionality and dimming.

Posted By: ice32
Date Posted: November 01, 2007 at 12:25 AM

Hey,

Are you only after them to come on when the dome light comes on? or are you trying to have both the dome light activation and a switched method?

Posted By: fugitivealien
Date Posted: November 01, 2007 at 5:18 AM

Yeah i'm just looking to have them come on when the dome does, however there is a switch on the control box for the lights, and might have to be taken into consideration wiring purposes.

Posted By: ice32
Date Posted: November 01, 2007 at 5:58 AM

well depending on the settings on the lights, id test if the 12v feed for the dome light changes when the light comes on and goes off, or if it's only the ground side of things, if its only the ground then you're just gonna have to tap into the ground circuit of your dome light.

The easiest way i see is to splice into your 12v and ground from the dome light and use them to power the neons, In theory that means that the neons only get 12v of power when the dome light does therefor giving you the effect your after. e.g coming on when the dome light does