What are the devices in these two parts of a schematic

https://imgur.com/a/mnnzq3O

On the left is probably the lighting for the 2005 Solara trip computer.
The schematic calls it the Upper Console Panel Sub-Assembly which I
think is the part above the radio (but the schematic lists the clock
illumination separately and makes no reference to the outside
thermometer, so that just lives the sort-of trip computer.)

I understand the LEDs but why zener diodes, and another diode (since
there is 12V DC at the top and ground at the bottom)?


On the right is almost all of what the Toyota wiring manual calls the
combination meter, meaning the speedometer and other meters in the
instrument cluster. I aassume the "rheostat" is the thing it has to
adjust the brightnees, that the LED (or more than one) provides the
light, but what are the strange things at the bottom and to the right.

They look like they are connected to transisors, but they have the 3
vertical lines, one of which in each set has a left-point arrow.

The manual has a list of symbols and it has LED, photodiode and zener
diode, but not the strange things in that picture.


BTW, was this an appropriate post for Imgur? Most of their posts sseem
to be more entertaining.

I though I had flickr and instagram but I can't find the login info. I
don't understand all this computer stuff.