The cruise control used to work just fine. I'd turn it on then press the set switch. Now it turns on but I can't get it to set, nor display as set on the dash indicator. There was a time where it was flakey, and I could get it to engage by repeatedly pressing the set switch. It later got worse, and it seemed that if I moved the the brake pedal from left to right or pull it towards the driver I could get it to engage, although someties it would disengage shortly thereafter.
I'm thinking the pedal switch may be flakey. Visually it seems to be depressed fully by the brake pedal at rest. How can I check the switch? Should I be looking at other pieces of the system? Thanks.

 

there is a vacuum source that connects to the intake manifold off of the cruise control mechanism in the car. check that to make sure its connected. my cruise turns on but doesnt work and this line is disconnected.

 

If it's a manual transmission there is also a switch on the clutch pedal. It's only purpose is to disengage the cruise when you push the clutch. There is another switch on the clutch pedal that prevents the engine from cranking unless the clutch is pressed all the way down, don't confuse them.
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Thank you both for your fast responses. I contorted myself, climbed under the dash, and removed the brake pedal switch. It tests fine with an ohmmeter. I then removed the clutch pedal switch, which does not test good. It will complete the circuit only if the pin is depressed further that the pedal can press it. In other words if I press the pin inside the housing I can get a reading on the meter. So, case solved! I must have been bumping the clutch pedal with my heel when kicking the brake pedal to get the cc to go.