I want to add an auxiliary brake light but need help finding the right wire. If I remove everything from the trunk including the foam "floorboards" there are a bumber of cables and connectors which must include the stoplight line. Any help ?? TIA Don (central VA)
Lots of looks but no replies, so I did it myself . . . Figured I'd put a brick on the brake pedal, then pierce the insulation of every wire looking for 12 volts. Good news is that every cable I could reach had a connector I could unplug. Did them all but the brake lights stayed on. Looked on YouTube for taillight replacement and found a number of hits, one of which was for Gen 5 (my 2026 PHEV). Followed the video and had the taillight assembly out by prying off a cover and removing 2 bolts. There was one 3-conductor cable (brown, blue, white wires) near the brake LED. Found that the white wire is ground, and the blue is brake. Spliced into that and it works. Added benefit, FYI . . .I put a small 12v lamp on my new brake cable and taped it to the back seat head rest so I could see it in the mirror. I wanted to see under what conditions the brake light went on: Obviously when I step on the brake; If I'm in B mode, level 3 (instead of drive), the decelerate sensor turns it on; in adaptive cruise as I catch up to another vehicle it DOESN'T turn on; If radar braking cuts in when approaching a stopped vehicle, it does go on; same if someone pulls out in front of me. Starting to like this car. Don
The only way to get the documentation is with a paid $30 two day subscription to the Toyota TIS system. At that point you can download one or thousands of wiring diagrams and other information as pdfs. Unfortunately the guy who downloaded most of TIS for gen5 decided it was beyond his ability to understand wiring so he did not add wiring to his zip file.
