Added Ambient Lighting, 2020 Lexus RCF, Puzzled At Outcome From Clock

Let me first by saying I've searched everywhere. I can't find this problem because to my knowledge I'm the only one that has done it or attempting.

I just bought a 2020 RCF a month or so ago. After looking at the door panels I realized there was no ambient lighting. They removed this feature. By default from Lexus when it's in park the doors light up above the trim. Then when you put it in drive it gets dim.

I took my door panels off to find that Lexus specifically made pieces to exclude the LED module. Not wanting to pay $300 per led module from Lexus/Toyota, and find out it doesn't work. I went on Ebay and bought a door panel for $100 because I saw it had the LED module in it. No surprise after taking my door panel off I was able to add it. Next problem is my car doesn't have the wiring. I didn't think that would be a problem and during my test run I tapped off power window control wiring harness. I found two wires (see video below) that control the voltage. No voltage when the headlights are off. 12v when the headlights are turned on, and when I adjust the brightness the voltage goes down to 2v and up to almost 12v! Yay, this is awesome!




I wire the one side up. Turn the car on and everything works. The come on with headlights, dim/brighten with the rest of the lights..etc. However, when I shut the car off, my analog fancy clock in the center of the dash stays illuminated while the ambient light is connected. If it is NOT connected the clock doesn't illuminate when the vehicle is off. Thought maybe it was because I only did one side. So I tested both sides together, and get the same result. The center analog clock will not shut off illumination until I unplug the led ambient lighting I added.

Wiring harness test:
Wiring harness test

Ambient lighting test:
Ambient lighting test

What would be causing this?! I haven't a clue.... And it seems super strange, since everything else works as it should and I would have been done with this if the clock would just not stay illuminated. I can lock the car, and it stays lit. Ambient lighting is off, entire car is off... but clock is still illuminated.

Probing more wires I found that I can simply just have the ambient lights come on when I turn the headlights on, and they shut off when the headlights are off/cars is off. The clock does not stay illuminated when I go this route but I completely loose the dimming aspect that it would match the same brightness with the rest of the interior lights.

What am I overlooking here? Both wires are the same on the window control switches. Thicker green wire and a thicker tanish/pinkish wire. I am assuming that the tanish/pinkish wire is the floating ground since if I use teh green wire and the black ground it only turns on when the headlights are on.

Appreciate any and all help. This is driving me nuts. I feel like I am 90% there. The hardest and longest part was probing and making sure I thought I had the right wires. By default they are doing exactly what I want it to do with the ambient lighting, I just don't know why the after affect is with the clock not shutting off and staying illuminated...

Makes me wonder if I should try another dimmer wire say on the radio harness or from another button? I don't know. I was trying to keep it all in the doors for ease and not having to run wire everywhere.

EDIT: I wanted to test something.
I used some LED strip lighting that I had. Connected it to the two wires I used in the video above and then shut the car off. The clock shut off no problem. Now I am 100% positive it's something to do with the ambient lighting module board. I'm not entirely sure what it is at the moment though. The simple LED strip had 3 leds and it had 3 onboard resistors. I am going to buy a few diodes and see if that fixes the issue with the lexus ambient lighting modules.. this is so stupid..lol. Might be getting closer though. I'll take the panel off and post pictures again.

LED Board:





My little LED test strip. 3 leds and almost the same resistors.


Thank you,
-Nigel

-------------
~NSG~

Certainly an interesting and puzzling issue! Have you tried asking in a Toyota/Lexus specific forum? Hope you get it solved! :)

So after digging around it appears there are a couple things going on. There isn't meant to be a completed circuit on the dimming wires from what other technicians are saying. And the way the LED module is wired up in series and parallel for the resistors is keeping something awake. Thus when the car shuts off the clock is being triggered to illuminate. As much as I'd love to have them dim with the rest of the lights. After playing around and dimming the interior lights all the way to the lowest setting, I realized that I couldn't see the interior lights/controls...lol So the fact of the matter is I probably will never dim them that low or at all.

I simply changed the wiring so that they come on when the headlights turn on. That way when the headlights are turned on, the interior lighting/controls turn on and so does the ambient door lighting.

Then when the headlights shut off, all the interior lights shut off. So the ambient lighting is only on when it's dark. The plus side is that the way I have them wired up my ambient lighting is on 100% brightness (still not crazy bright), but doesn't dim like the default setting. Lexus by default has the lights at 100% brightness in PARK. But then dims down to 50% when it's put into DRIVE. Everyone on the lexus forum hates it and says they can't see the ambient lighting and wishes it was brighter or stayed at the "PARK" illumination.

So I guess it was a blessing because I have what most people want on the forums. And on top of that, to my knowledge I'm the only one that has retro-fitted door ambient lighting on the newer model year. So that's cool!

-Nigel

-------------
~NSG~