Cruise control switch logic

[Wallace White]

I'm trying to get the cruise control working on the 5k again, and I'm
not sure how one of the circuits is supposed to behave.

There are four cruise switches in the stalk. As shown in the Bentley,
they are (right to left) Set, Resume, On + Resume, and my mystery
switch. The diagram suggests that this switch is closed when the slider
is set to On or Resume, basically like the adjacent switch.

The first three switches are connected to +12V and test fine.

This leftmost switch is not connected to +12V but instead to the brake
light switch. Its "output" then runs through the CC's clutch and brake
switches in series, and then to the CC module. That is:

     o  +12V
     +
    |
  ==|   Brake light switch
    |
     +
    |
  ==|   CC stalk mystery switch
    |
     +
     |
   ==|  CC brake switch
     |
     +
     |
   ==|  CC clutch switch
     |
     +
     o  CC module, pin 3

Since the brake light switch is normally open and the CC brake and
clutch switches normally closed, is current ever flowing through this
circuit--regardless of the CC stalk switch's setting?

I ask because I don't understand the Bentley's test of this switch: test
for continuity between ground and the disconnected brake switch
connector (the highest pin, I guess), with the CC module disconnected.
Should be 0 ohms when the switch is On, infinity when Resume.

Huh? There's no path to ground here, unless it's through one of the
other circuits hanging off the brake light switch.

Anyway, I did try it and got mega-ohms when on, infinite when resume.
Maybe I do have a bad stalk switch?

Thanks,
Wallace
'87 5kcstq 203k