I have the same problem with the orange indicator light on the AC knob being out. Because this post shows up in any Google search related to this I wanted to share what I've learned.

This style of AC control unit isn't that common, 2016 +/- a year or two.

I removed and fully disassembled this assembly yesterday. There is no bulb, it is an LED soldered to a circuit board. This lines up with another thread talking about upgrading to LEDs and that this is a soldered LES. I might be able to figure out soldering a new LED in, but I haven't been able to find any information on this. Also it was in a tricky location recessed behind the AC button.

Going through Toyota parts this assembly is only sold as a unit, no parts within it. It sells for about $600. Searching ebay I find the assemblies from junked 4Runners are going for $125. I appreciate the ebayers including the picture of the wrecked 4Runner in the listing.

So yeah I'm spending $125 to repair the little orange indicator light.

I post this in the hopes that someone can tell me how wrong I am and someone else is pointed to a cheaper solution.