Problem was intermittent drop-out of 99 Buick Century cruise-control.
Removed felt cover belows steering column (easy); Observed two
nylon switch-assemblies....both operated simultaneously by metal
tab attached to the brake pedal. Both were quite loose....mounted
by a nylon nut on a threaded shaft.....quite difficult to reach or
maneuver to re-tighten the nylon nuts . I gave up on trying to
tighten the nuts , but there is a convenient bolt-and-washer that
holds the steering column, nearby. I took a small length of steel
wire (6 or 7") under the bolt/washer. I used a piece of #10
copper-clad steel, but larger size coat hanger wire (or double up
with the smaller size) would probably be strong enough. I improvised
so that the shorter end extended up to hold the smaller upper switch,
and the longer end extended behind the larger switch to hold them
forward toward the brake pedal. Trick: leave the bolt/washer loose
about 1/8" while positioning steel wires, so that tension will be
added when the bolt is tightened. (This is the same action that
would occur if you could tighten the nylon nuts).
I dobbed some RTV adhesive on the steel wires to prevent them
from slipping due to vibration.
Note: A quicker and easier fix might be to improvise a tin or
perhaps even alumimum foil "shim" to wrap aroung the steel tab,
or plate that is attached to the brake pedal. However, this might
only be a temporary fix because, the nylon switch assemblies would
probably continue to shake still looser.