Controls of unknown function ('70 1600)

[Jason Simpson <jason@xio.com>]

There are two controls on the dash I haven't figured out yet.

One is the one just below the wiper control, second down on the far left
of the dash. Here's a rough ASCII depiction of its label:

   \  |  /
    \ | /
 |\       /|
 | \ \   / |
 |  ) O (  |
 | /   \ \ |
 |/       \|

It appears to be a twist-only knob, and it seems to rotate perhaps a
quarter-turn.

The other control is labeled "S/BRAKE" on the center console next to the
radio and, when pulled, illuminates a round red light with a "B" on the
dash below and to the right of the fuel/temp/etc. gauges.

What are these controls?

        -jrs