5kcstq Cruise Control troubleshooting questions

[ewendell@iolinc.net (Wendell, Edward)]

Well, the time for me to sample the list's collective wisdom has come
once again. I usually just make sure I read and digest every post
instead of asking tons of useless questions but this time I've exhausted
all other options known to me.

	The patient is my much beloved but previously abused and neglected 86
5kcstq with a list of problems. The most important problem at the moment
is a non-fuctional cruise control. The Bently manual that I have access
to does not seem to be kind enough as to provide me with something as
elementary as a description of operation or a troublshooting tree. All I
am left to work with is the wiring diagram. Using my wits and said
diagram I have checked the control switches, power source, brake and
clutch switches, and associated wiring. Using a vacuum pump and
associated gauge I have checked proper operation of the pump(by
jumpering power to it and clamping the relief line), servo, clutch and
brake valves, and associated hoses. I have also substited a known good
control module with no success. The only thing that I do not know how to
check is the speed input signal. My wiring diagram suggests that it
comes from the speedometer via the blue/white wire. My speedometer
fuctions properly (for now anyway), but I have no idea what kind of
signal I should be seeing at the cruise control connecter. Should I be
seeing the 8 volt pulsed signal that the speedometer sender on the
transmission puts out or something different? I currently see a
continuous 8v relative to chassis ground that does not vary with left
front wheel speed.

Thanks for your time,
Roy Wendell
86 5kcstq-college student daily driver, 154,300 mi. and still kicking