Along the same lines as Gulfsailor posted...
Did you participate in a sea trial before buying the R-27, and if so did you checkout the autopilot for calculating a safe course and engaging the autopilot to steer the course ?
Do you select a destination by Name, then select Done, then select one of the destinations found (if several displayed), then select Guide To, and then select the warning message as OK and then select engage Autopilot ?
Do you have the Garmin Autopilot documentation ? If so have you followed the instructions carefully ?
If all this fails to get the Autopilot to steer the selected safe course, then call Ranger Tugs service and describe the issue to them for help.
Typically, if your boat is equipped with Auto Pilot then during the sea trial the Auto Pilot is checked out with you onboard. Sometimes the Auto Pilot's electronic compass needs calibrating, as was my case during the sea trial, and Andrew Custis took the boat back to the factory to have it fixed.
It's important to have the Auto Pilot checked for proper operation so that one can feel comfortable relying on it for safe tracking etc.
Post back here what you find out... as we can all learn from issues like this. Thanks... 🙂