Steering wheel control wiring for W53828 radio

[Upbeatal]

Hi all,  New to this site and need help. Recently bought 2009 T27 Avensis. I'm in the process of installing after market Chinese Android head unit. Everything wired up ok (Speakers, power) except the steering wheel control wires. Can anyone tell me which wires/pinouts relate to KEY1, KEY2 and GROUND for steering wheel control.  The full details of the original unit are: Model No 86120-05150. ID No W53828, Assembled by Panasonic. A full guide of all sockets functions and pinouts would be very much appreciated. I did find another tutorial that shows the sockets and wire colouring but not what the wires are used for.  Cheers

 

[FROSTYBALLS]

Moved to the Avensis club.

[Konrad C]

I am trying to recall some info from within the forum. Read some of the replies which also refer to steering controls.
 

Autoleads supply a steering wheel control interface, for third party stereos - PC99-209. You have to then use PC99 patch lead from the interface to the relevant brand of stereo. Maybe the chinese stereo uses the the same interface as Sony, Pioneer, Kenwood etc. Check the instructions. 
I will see if I can find more info.