Hello,
The first thing I would look at is the IF-NMEA2k2 converter. To receive RMB data through the converter (RMB is Navigation Route/WP Information which you would need for the pilot to respond to "navigate here" function) you would first need to make sure its set to high speed mode.
High-speed mode is set up by having the purple and black wire spliced together and the orange wire will be cut and not connected to anything. After you change the converter modes you will need to secure power from the converter and re-apply power to properly change configuration.
Also you need to make sure the BAUD rate of the Garmin auto pilot can be set to a BAUD rate of 38400 in order for the high-speed function of the converter to properly interface.
By quickly looking at the specifications of the TR-1 pilot, I found that the Garmin pilot can handle this high-speed rate, however I'm unable to verify if this can be changed at all in any settings.
As long as the IF-NMEA2k2 converter is set up in high-speed mode, the pilot should work and interface properly. If this issue still exists when converter in high-speed mode then I would recommend Contacting Garmin to verify specifications and correct settings of your pilot.