Cruise control failure

[smarks@ns.net (Steven N. Marks)]

Anyone experience this one...

I have an 87 5000Sq w/ 117k.  On a trip to the Giants doubleheader this
weekend, I turned on the cruise control.  Worked for about five miles and
than shut itself off as if I had shut it off at the switch.  Tried to turn
back on and it engaged, than shut down again almost instantly.

On the way home, I tried again with the same pattern... 5 miles, shut
itself off.  Tried again, shut itself off within a few seconds.

Go figure... The 5 to southern CA requires that it be working for future
road trips.  Any thoughts?

Thanks in advance.

Steve