Anyone with a '21 Limited, Nightshade, or TRDPro willing to take some voltages for the wires going into the low beam connector on the headlights?
I've been digging through the wiring diagrams and repair manuals on
https://techinfo.toyota.com/ and I think I've figured out how the '21 lights work. Only thing I'm not sure about is the voltage that the ECU is supplying to the low/high beam LED module and the solenoid for the low/high projector shade.
There should be wire loom with 3 wires going into a 4 wire socket on the headlight. I think the wire colors are Red, Blue, and Black. While the truck is running (engine on, but in Park), I'd like to know the voltage of:
Low Beams On:
Red to Black voltage
Blue to Black voltage
High Beams On:
Red to Black voltage
Blue to Black voltage
Please don't do this unless you're comfortable testing wire voltages. Don't wreck your truck or hurt yourself.
I think the voltages should be around 12 Volt, but there's a new LED driver module in the '21 ECU that supplies this current so I'm not sure if it's 12 Volt or a little higher like 14 or 15. For retrofitting these headlights to an older truck we'd want to match this voltage to get full brightness out of the LEDs, but also not over drive them and burn them out.
Once I finish figuring out the wiring for the new lights and how to retrofit them on an older truck I'll post some info here.
There might even be potential for '21 models without the bi-low/high LEDs to make them bi-LED, but to know that we'd need more photos of the wiring on these models. It might be a long-shot, but the lights could be wired for the bi-LED function from the 4-wire plug to the projector, but not be using the solenoid wire which is what needs to be activated to move the high beam shade up for high beam mode.