If as you say I'd need to replace ECU & relays then what about using a conversion system such as a DEI545T unit to facilitate auto headlights. What wires would I need to tap into.
Hope this helpshttp://www.sonicelectronix.com/item_17931_Directed-545T.htmlRegards,Colin
In your response you have described the resistance ladder network that enables the steering wheel controls to be recognised so the corresponding switch is correlated to the resistance relating to an individual steering wheel control. The light switch does not operate in this way as it is hard wired to the light control stalk. I thus lost faith in your response above and feel I'd be better off talking to an Auto Electrician with access to the Prius wiring diagram.
The light switch does multiple functions via varying resistance through only 2 wires(for the headlights) through the body ECU. This is from the wiring diagram, which I studied closely looking for a way to install the system you wanted. I am a Toyota master and Hybrid certified and I never mentioned anything about steering wheel controls.
Hi Toyota Tom
Thank you for your answer above and it is perfectly satisfactory. Had I had a straight aswer like yours from the other guy I would have been more than satisfied. The only reason I didn't completed the "Rate to Finish" tab is that it told me I'd be up for yet another $22. Since I'd already parted with $22 already to the previous guy I've elected to reply to you and let you know what I thought. Not sure where to go from here to finish this off with out yet more expence.
Cheers and have a great 2013.
Thank you for usingjustanswer.com, my name is Joe and I will be happy to assist you with yourconcern today.
Just seeing if you stillneed assistance with this problem?