Arifsach

I have a 2016 GS300H and have noticed that the panel for the mirror and a few other switches do not illuminate. They were working fine before we tried to fix some led strips to the door panel. Is this a door ECU problem? Is the ECU gone or would it just require reprogramming? The same applies to the passenger side. Window switches all illuminate just the section of mirror, door lock/unlock, fold etc that do not illuminate any longer. Can someone please advise what this is? Lexus have replaced the panel but it is the same issue.

EAST

Those lights are powered off the left and right door multiplexer. It controls a lot of things within each door.

The left hand /driver side lock/mirror switch is illuminated by a white (pin 13, ground) and green wire (pin 3, positive). You check on a 20 pin connector that has pins 1-10 on top row and 11-13 on bottom. I'm guessing this plug goes into the window switch area. A sanity check would be to check for continuity the white wire and ground, just to make sure it is grounded, then checking the white and green for voltage.

For the right side, it'll be pins 1 (green, positive) and 6 (white, ground). It'll be a 12 pin connector (1-6 on top, 7-12 on bottom). But this will only tell you if the multiplexers are outputting that illumination power. If all other functions are working (like moving the mirror or illuminating the door courtesy light at bottom when you open a door), then the CANBus communication should be working. Easier to confirm if you had a scanner.

When you say Lexus replaced the window switch, did they do any diagnostics to see if multiplexer was providing power? Or did they just replace because you asked them to?​​​​​​