peteharvey

Does anyone know if it is an easy job to DIY "rewire" the rear brake lamps in a 2013-2015 4GS so that "both" the outer and the inner "L" light up, and at full brightness - on braking?
Presently only the outer L lights up and at full brightness on braking, meanwhile the inner L only lights up at half brightness when the park lights or head lights are turned on.

Park light & headlight: both L's illuminate at half brightness.



Braking: only the outside L illuminates, and does so at full brightness. To me, this is a bit unattractive.
How can we get the inside L to illuminate, and at full brightness - on braking?

peteharvey

From the research that I've done so far, each red light has 3 wires:
1) Red wire for high amperage braking,
2) White wire for low amperage tail lights, and
3) Black ground wire to return the current back to the black negative terminal of the car's battery.

So theoretically, the outside L lights are fed with all three wires, while the inside L lights are fed with only the low amperage white wire for tail lights, and a black wire to return the current to the negative terminal of the battery.
If this is true, then it's just a matter of locating the red high amperage wire as it travels to the outside L lights, and such a red hi amperage wire should be absent from the inside L lights.
Then it's a matter of Teeing off the red high amperage wire, and sending a new red high amperage wire to the inside L lights, such that when we press the brake pedal, all four L lights illuminate at full brightness.

Apparently I might have to finish off by checking the amperage rating of the fuse, and if necessary, use a bigger fuse for the four L brake lamps?
Also, can the inner red L-shaped lamps handle the higher amperage & hence higher wattage for brake lighting?
I must investigate if all this is true...

peteharvey

Below is a disassembly of the Lexus 4GS outer and inner L-shaped tail lights.

peteharvey

In the video below, someone has actually turned the 2005-12 3GS's rear fog lamps into rear brake lamps, to give a rear four-light brake lamp look!
Notice how the rear fog lamps can still be switched on independently for driving in foggy conditions.