changing trunk open button possible??

I spoke with the service manager at my dealership about this issue. He said the option is not available on all levels of trim, and running a wire would be necessary. I would say it's not worth all the trouble.

 

I'm sure it would work, but I can't imagine the cost.

 

If you want to proceed I would suggest you start with looking up the wiring diagram on techinfo.toyota.com or TechDoc New Generation for the car with the option you want and comparing it to the wiring diagram for the car you have. Once you find the wiring diagrams you can then click on the link to locate the parts on the vehicle to see where each terminal is located. Than you can confirm which wires/parts your car would need to make your car match the car that has the rear hatch lock button.

For looking up parts I find amayama.com a great free resource with parts diagrams linked to models and trims. The parts diagrams on amayama.com are in black and white and often not as high resolution as the US dealer parts sites so once you find the diagrams on amayama.com I often find it useful to locate the same diagram with color and higher resolution on US dealer parts sites.

It has been a while since I have subscribed to the toyota-tech.eu but if I remember correctly you could look up parts with a paid subscription whereas techinfo.toyota.com does not have a great user interface for looking up part numbers even with a paid subscription. Toyota-tech.eu used to let you purchase a couple hours of access and that may be all you would need whereas techinfo.toyota.com shortest subscription is a 2 days.

I imagine there is a similar web site for South Korea or Asia but I am not aware of what it is. I wouldn't imagine it would be a terribly complicated circuit but I am pretty novice when it comes to modifying cars.