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5k A/C programmer debugging

I'm not exactly sure what to make of the problems with my A/C

1) One of the vacuum solenoids (the footwell one) won't hold vacuum on
the vacuum side, but the others do. They are supposed to hold vacuum,
without any voltage applied, right? But holding vacuum can also indicate
that the solenoid is swollen shut, I understand, so I'm not sure how to
diagnose it. The whole programmer does rattle, but it's hard to tell if
I'm hearing two or three or four rattles.

At any rate, getting a junked programmer and replacing solenoids would
seem to fix this, but...

2) Two of the solenoids (footwell and center-vent-all-the-way [not the
bi-lev one]) are never seeing voltage during operation in the car.
Stranger still, the recirc/heater valve one sees voltage when "OFF" (as
it should) but not when "AUTO LO" (as it also should). Maybe it was just
being flaky. The bi-lev one sees voltage at all the right times.

All the pins that I can check according to the Bentley (which doesn't
include the 4 pins from the head unit that actually control it) are
fine. The board itself looks fine, except for a light brown area on the
circuit-side, opposite to two of the small brown caps, which I take is
not a problem. Anything else to check for?

3) My programmer (March '86) has three solenoids in a line and the
fourth separated from them. The Bentley depicts all four sort of in a
line but staggered. Is one version an improvement over the other? Then I
would know what to look for in a junked one.

Many thanks in advance, as always.

- Wallace
  '87 5kcstq 150k