CC help
Most of the units I have worked on had a separate normally closed switch on the brake pedal(or in the case of the later models, with the pressure switch on the master cylinder that burns everyone's truck up). That means the amplifer requires a 12v signal from this switch at all times to work, and if the switch went bad or a wire or a fuse burnt out, the cruise would not work at all till it was fixed.
They only have one brake switch and it is the same brake switch and wires that is used for the brake lamps.
They all have a Vacuum Dump valve on the brake arm (photo below).
None of the them have a pressure switch on the master cylinder from 1976-1992.
The system that Dave F is talking about started on trucks in 1993.
Photo of the Vacuum Dump Valve and it causes a lot of non working system if not adjusted right:
http://i54.photobucket.com/albums/g9...mDumpValve.jpg
The 1976 wiring diagram:
http://i54.photobucket.com/albums/g9...CCF-series.jpg
The 1988 wiring diagrams:
http://i54.photobucket.com/albums/g9...ol/PG113-1.jpg
and
http://i54.photobucket.com/albums/g9...ol/PG114-1.jpg
/
If you would care to email them to to me maybe I can help you more.
subford@gmail.com
















