How to make Footwell light on when driving at night?

Reply Subscribe

Thread Tools

Search this Thread

Oct 9, 2025 | 07:50 AM

ShadyLexIS

Thread Starter

10th Gear

Joined: Jul 2006

Posts: 11

Likes: 0

From: FL

How to make Footwell light on when driving at night?

Is there a way to make footwell light on all the time when driving at night and not just on/off when open/close door.

This is for the latest model 2021-2025 IS350

Oct 10, 2025 | 11:28 AM

isfree

Pit Crew

Joined: Oct 2019

Posts: 106

Likes: 100

From: California

There's no setting to do that but its possible. VLEDS made a dual output ambient light kit for the 21+ Lexus IS that fades on/off with the door opening and also fades on to a lower level when headlights are on, but it's discontinued or out of stock now. So I had to DIY it. It's complicated but I can write a full tutorial if anyones interested

Basically, I built a circuit to do it without cutting any original wires. The factory wiring harness plugs into the footwell light housings using connectors. Connector pigtails are available on ebay/aliexpress:

90980-11148 plugs into the light housing
90980-11159 plugs into the factory wiring harness

Get two of each connector pigtail, building an extension cord. Wire it so the positive passes through (the lights are switched using ground). Intercept the ground with a diode and N-mosfet, so that both the ECU and mosfet can ground the lights, but when the mosfet grounds the light it won't affect the ECU. Connect gate to the TAIL fuse or a microcontroller, I used a microcontroller to dim the lights instead of full brightness at night. Otherwise just connecting gate to TAIL fuse would make it full brightness at night. Remember to add protections for transients, load dumps, fuses, etc.

Basic circuit:
https://www.falstad.com/circuit/circ...kJkMIA5ojBhwgA

Last edited by isfree; Oct 10, 2025 at 11:54 AM.