Cruise control guidance requested

[indyhog]

The cruise control has not worked since before I bought it but I have check the basics and want know what to look at next.

-The brake on/off is ok and fuses are ok that where applied in the associated recall for fires.
- fuses in dash are all ok
- all break lights are functional
- Switches in steering column seem to operate.
Voltage checks across the blk and lt blue wire w/o any buttons depressed are 6.6v
pressing the "Off" gives 0.0v
pressing the "On" gives 12v
pressing the "Coast" gives 0.75v
pressing the "Set" gives 2.75v
pressing the "Resume" gives 4.7v

What repair manual with wire diagrams would you guys recommend buying?

Thanks a lot!