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Tapping into footwell lights for constant 12V - tripped fuse?

kpeng

Member
Dec 1, 2019
451
858
Gainesville, FL
I'm trying to hook up an EL wire to light up the trim around my center console, and was trying to tap into the power wires for the passenger side footwell light for power. As soon as it was hooked up, the footwell light stopped working and my EL Wire never lit up. Did I trip the car's fuse for the ambient lights? I know they can sometimes act weird and self-resets after a couple hours. I'm curious if once it resets, both the footwell and the EL Wire will start working...or if I cannot add that additional little bit of draw at all.

Anyone experience this?
 

Jeremy.j.hall

Member
Jun 27, 2020
18
9
Uk
Found a way of taking footwell feed for switching the lights, and using 12v socket power.

Small electronic circuit involved but means control these lights via touchscreen, and on and off when car locks/unlocks.

Happy to share circuit if people interested

Can't take credit - My dad was the brains behind it all!!

J
 

ochompsky

Member
Oct 26, 2020
96
77
md
Found a way of taking footwell feed for switching the lights, and using 12v socket power.

Small electronic circuit involved but means control these lights via touchscreen, and on and off when car locks/unlocks.

Happy to share circuit if people interested

Can't take credit - My dad was the brains behind it all!!

J

please do share
 

kpeng

Member
Dec 1, 2019
451
858
Gainesville, FL
Found a way of taking footwell feed for switching the lights, and using 12v socket power.

Small electronic circuit involved but means control these lights via touchscreen, and on and off when car locks/unlocks.

Happy to share circuit if people interested

Can't take credit - My dad was the brains behind it all!!

J

Please do!!! I was thinking about using a relay, but this may be better
 

Jeremy.j.hall

Member
Jun 27, 2020
18
9
Uk
Please do!!! I was thinking about using a relay, but this may be better

Relay was the first attempt... on its own worked when lights were bright, but not enough juice to keep it pulled in when the footwell lights dimmed. (in gear). :(
Next attempt involves diode, transistor, cap and relay. Need dad to pin down the finer details of what these colourful components are. He just turned up and helped me solder them together...

Will share as soon as able
 
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Jeremy.j.hall

Member
Jun 27, 2020
18
9
Uk
Hi All,

Follow on from my post earlier.

I Attach the circuit diagram for this ambient light sensing circuit. This takes a very small amount of power (Max 3mA) form the ambient light positive feed wire and uses it to switch a relay connected to a much bigger 12V supply (i.e. cigarette lighter)
Used in my Model 3 to switch Basenor RGB Led kit on and off with the ambient footwell lights.

Feel free to copy the circuit and use it.
I will put together & post kits of parts for anyone who is interested, and even build the board for you if you like (for a small fee!)

Linked

Disclaimer - If you build this and plug it onto your Tesla - it is at your own risk (obviously!).

Relay HFD23/012-1ZS
Diode 1N4143
Resistors standard 0.25w 1%
Cap 0.47uF Metal film
Transistor BC337-40

Happy tinkering!
 

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ochompsky

Member
Oct 26, 2020
96
77
md
just wanted to drop a message and say the relay posted above by jeremy works perfectly. it's a must have for anyone with these lights.
 

asian_xl

Member
Apr 24, 2016
285
196
Hong Kong
The e-fuse is sensitive, I added another 5w bulb to the trunk, so it lighted up both reverse light (European model has rear fog light), all the lights stopped working for a half a day. Even the 12v outlet cannot handle too much power, I won't even let me use the 12v power tire pump for 10 seconds.

I've seen people tap the power from the door map lights, seems fine with all the dash cams
 

Jeremy.j.hall

Member
Jun 27, 2020
18
9
Uk
Morning everyone,
Adding to my original basenor light tube kit, I have now put rgb strips in the footwells.
There was (luckily) spare solder pads for 12v and rgb in the Basenor controller. I have connected to this, and the new footwells follow the same colour and pattern set for the light tubes.

YouTube

Happy to build and post relay switch board as posted in an earlier thread. Circuit for self build attached in an earlier post.

Happy tinkering
J
 
Last edited:

bbush

New Member
May 28, 2021
1
0
Allentown, Pennsylvania
Hi All,

Follow on from my post earlier.

I Attach the circuit diagram for this ambient light sensing circuit. This takes a very small amount of power (Max 3mA) form the ambient light positive feed wire and uses it to switch a relay connected to a much bigger 12V supply (i.e. cigarette lighter)
Used in my Model 3 to switch Basenor RGB Led kit on and off with the ambient footwell lights.

Feel free to copy the circuit and use it.
I will put together & post kits of parts for anyone who is interested, and even build the board for you if you like (for a small fee!)

Linked

Disclaimer - If you build this and plug it onto your Tesla - it is at your own risk (obviously!).

Relay HFD23/012-1ZS
Diode 1N4143
Resistors standard 0.25w 1%
Cap 0.47uF Metal film
Transistor BC337-40

Happy tinkering!
Hey Jeremy,

I have a very similar circuit in my car (less the low-pass filter you have), and am trying to implement a filter myself. I had it all ready to go, only to realize that the lights are dimmed when the car is in drive (I assumed it was just providing the lights with the full voltage of the 12V battery). I do not have an oscilloscope to confirm, but I assume this is some sort of PWM signal going to the footwell lighting. But I was taking measurements at different times, and the signal going to the footwell lighting varies tremendously (like from <20% up to ~90%+ duty cycle), and it doesn’t seem to follow much of a pattern. Regardless, I am having a hard time to make this work. From what I have calculated so far, I don’t think I will be able to get it to trigger at the lower end of range of duty cycles its providing. I need ~2.5V to trigger the relay, and do not think I can get there in these cases. I am just wondering if your setup has worked in all situations?

Thanks!
 

Jeremy.j.hall

Member
Jun 27, 2020
18
9
Uk
Hey Jeremy,

I have a very similar circuit in my car (less the low-pass filter you have), and am trying to implement a filter myself. I had it all ready to go, only to realize that the lights are dimmed when the car is in drive (I assumed it was just providing the lights with the full voltage of the 12V battery). I do not have an oscilloscope to confirm, but I assume this is some sort of PWM signal going to the footwell lighting. But I was taking measurements at different times, and the signal going to the footwell lighting varies tremendously (like from <20% up to ~90%+ duty cycle), and it doesn’t seem to follow much of a pattern. Regardless, I am having a hard time to make this work. From what I have calculated so far, I don’t think I will be able to get it to trigger at the lower end of range of duty cycles its providing. I need ~2.5V to trigger the relay, and do not think I can get there in these cases. I am just wondering if your setup has worked in all situations?

Thanks!
Hi,
Sorry for the slow reply, hope you have it sorted now?!
We too assumed the leds are dimmed with PWM, but have not put a scope on to confirm. We have not needed to as the switch circuit used has worked flawlessly for 10months now. It did turn off once and I thought it had broken, but I found out a software update had switched off the ambient lights!

The trick (I believe) is using the little capacitor to smooth the input to the transistor so it is always enough to saturate the transistor and this passes enough current to keep the relay energised. It is a very low power relay too... (12mA)
Let me know if you need more help
J
 

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