92 Ford Van Cruise Problem
 

I've got an RV built on a E350 with the 7.5L engine. Cruise won't work and I'm looking for the electrical drawings or a diagnostic manual. I've checked and the steering wheel switches appear to be working. The brake switch and the pressure switch appear to work. I'd like to know if the speed is fed back to the controller as an analog or pulse signal to check that signal. I'm about the replace the servo/controller, but don't want to unless I've ruled everything else out.

Thanks,
Michael