Need some wiring help

[Cowjut]

I want to know how i can fish a new wire to the dome light or where the dome light wire harness leads to so i can tap into it. Installed leds under my car, i want them to kick on and turn off with the dome light. Any help would be appreciated

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[Triple_peaz]

I think the dome light is constant power, don't quote me but I tapped into that on my 8thgen for a radar detector and it stayed on until I would manually turn it off

 

[Cowjut]

Well any idea on how i can make my light dim on and off along with the dome?

 

[ne0guri]

Well any idea on how i can make my light dim on and off along with the dome?

Isn’t there a fuse box where those wires go to? You should be able to tap into that if I’m not mistaken.

 

[charleswrivers]

Simple. Turn in your dome light. Shut your door. Check your fuses to see if one is called something that should correspond with the dome lights. Regardless, you can pull fuses until the dome light is out. Mind you, if you pull the fuse corresponding with your radio, you'll likely need to enter a code for put to work again.

The only question now if there is either 1) a separate circuit on a timer to power the dome light. My thought is it'd have to be, because manually turning on a done light should defeat them turning off on a timer. Flipping them back off inside the timing sequence would likely default back. Since it's all just DC we're playing with, the sources get effectively auctioneered, with the highest voltage source dominating and running the circuit. As the timing circuit dims and ultimately extinguishes the light, the constant on would maintain the light regardless.

With the fuse pulled to make the light be out via the switch, by opening the door, you'd know whether the timing circuit is also powered from the circuit, downstream somewhere or off another circuit.

Whether this is from the source downstream of the fuse being pulled being split into a parallel with a timing circuit... I don't know without a wiring diagram. The timer is almost certainly somewhere downstream the fuse, so trying to wire a parallel circuit right off the fuse will probably result in an always-on. You can go wild and add your own timers, but that'd get messy quickly.

if there is a option to control the delay from the headunit, that in itself is likely the source of the power. Since the dome timing is based on the doors shutting (Jenny has the car so I can't verify this at the moment) that starts the timer... and I think instantly causes a step drop in light... it holds... then dims from that point.

You should note the power draw of your LED light strings. It should be minimal, but you still need to factor it and the tiny incandecent light in and ensure you're not overloading the circuit.

Again, I haven't seen 10th gen wiring diagrams around other than some audio stuff. 9th gen civics are quite similar abd might be pretty comparable. Based on a minute if searching, the fuse looks like it's in the engine bay... fuse 21? Check your model year... there were a few differences.

https://www.google.com/amp/s/fuse-box.info/honda/honda-civic-2016-2018-fuses

My gut is timing side is driven off the headunit. I can swore I saw a time delay adjustment for it in there. I know there's a delay adjustment for lights when you are out of the car. Those still just control the relays... and the relays do the power interruption, but I bet there's plenty if capacity to drive the small interior lights.

 

[Cowjut]

Isn’t there a fuse box where those wires go to? You should be able to tap into that if I’m not mistaken.

I hooked it into the "interior light" fuse and it had contant power. Ive tried every other fuse that sounded like it could possibly work, pretty sure hardwiring it is the only way

 

[charleswrivers]

I hooked it into the "interior light" fuse and it had contant power. Ive tried every other fuse that sounded like it could possibly work, pretty sure hardwiring it is the only way

If the headunit has an option to change the delay, it's the power source once the delay is occuring. It's just a parallel circuit wired in. You'd need to tap that point but ensure you aren't overloading it. Also, those LEDs may not work with the doors open... they may only work once the door is shut... the dim. It sort of depends how the circuit was setup.

 

[SCOPESYS]

You might consider powering your under-car lighting from the Brake switch (via a relay), so that the lights can only come on when the brake is set.
That way, you cannot drive on the road with them on .... (by mistake)

In the United States of America, certain underglow lights can be considered illegal.[5] The colors could be distracting to the drivers or the drivers could easily confuse them for police officers. For this reason, colors like blue, red or any kind of flashing lights are banned from public streets in some states. The laws on the underglow of a car depend on the state and if they believe that it could be harmful for the drivers on the road. Almost all the states prohibit the colors green, red and blue because these are used for emergency purposes only. States where there is a lot of traffic and have a lot of cities have stricter regulations due to the high risk of crashes. Police and the state government officials believe that bright colors at night could be dangerous for people who are also driving. Ground effects lighting is illegal in the state of Michigan.[6] In California,[7][8] underglow lights are allowed to be used in places other than public roads and there could be a penalty if found using them in public roads. In Vermont, there is a penalty if underglow is turned on while driving. In Alaska, underglow lights are allowed as long as the color is white, yellow, or amber.

Underglow or ground effects lightings are illegal in the province of Alberta, Canada. The use of these lightings are prohibited under section 4 subsection (4) of Alberta's Vehicle Equipment Regulation.[9]

In 2019, Florida is poised to pass legislation to affirmatively make underbody lights legal.[10]

https://en.wikipedia.org/wiki/Underglow​

 

[Cowjut]

You might consider powering your under-car lighting from the Brake switch (via a relay), so that the lights can only come on when the brake is set.
That way, you cannot drive on the road with them on .... (by mistake)

​

I just want them to come on when i get in and out of my car, would be cautious not to turn on while i drive. Wiring them to brake would leave the lights on all night with the brakes

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