Does anyone know what wires are up shift and down shift on the tiptronic steering wheel. 99 lexus gs400

 

You can pull the airbag off and look behind it and identify the wires. Disconnect your battery first to be safe.

Alternatively, if you have a pinout of the ECU you can check wire color at the connector there. I think it's something like STU for shift up and STD for shift down. I added my own wires for Eshift when I went with the Aristo setup, so I don't know the color.