So I was playing with some old master switches some co-workers had laying around from previous repairs. Disassembled the switch to find something VERY interesting...
Toyota's master switches are printed circuit boards with memory chips and other components. They are pretty much their own module, which isn't that surprising since almost every car manufacturer is going to this... What IS surprising is that all the switches I took apart were Driver's Side Only Auto up & down and yet ALL the switches on the circuit board are already printed, chipped, and pinned for full auto.
What Toyota apparently does is utilize a different rocker (the plastic part you actually push/pull on) and add two extra plastic pins when they want a switch to be fully auto.
Edit- I'm sorry jumped the gun there, the design I am referring is used in the similar year Sienna, Highlander and uses push pins and buttons like a keyboard or calculator, the 4Runners use a slide switch, different mechanics all together. But the switch itself is still set-up like a module, so my theory is still sound. I wanted to correct that real quick
Unfortunately you cannot buy the rockers and pins separately. But this tells me that the switches themselves are already "wired" so to say for the function, they just lack the physical mechanism. Much like how GI-Spec M14's still retain the full auto function, but the engagement cam is not installed.
You should in theory be able to purchase a GX470 Master switch and swap it out for All Auto function fron the Driver's Side. The connectors should be the same. I'm going to hunt for a cheap GX470 switch, I don't feel like paying $200+ for one right now...
Hope this helps! :frog: