Thanks for all the info! i have a 2011 Roadster and my GPS recently went totally kaput after being problematic for awhile (showing 6th gear at timed, problematic neutral light...). However, after reading some of the comments, I took the GPS out and it seems different. Instead of the circular contacts (similar to all the part diagrams) I have a unit the has what seems like one central contact and one pin in the periphery that when positioned aligned with the to screw of the GPS, fits into a hole on the transmission. I even bought a used unit that supposedly fits and it looks the same as in the diagrams, fits nicely into the GPS mount, but is completely different than mine, and I doubt that it will work. Both units (mine and the used one), have two wires coming out of it. What am I missing?
Sounds like the used unit is for 04-09 Rockets, not Roadsters. The part diagrams only seem to show the 04-09 design alright, they didn't update them for the Roadster GPS which has the pin built in and the contacts concealed inside. What I don't get is why the one that came off your bike, apparently has the pin built into it but has only 2 wires..?
History of GPSs in Rockets - bear with me now because this can get a bit complicated;
This GPS here T1190814 is the one you'll find on 04-09 Rocket III / Rocket III Classic / Rocket III Classic Tourer.
There is a rounded pin on a spring that sits into the gear position shaft on the transmission, the pin rotates around and contacts the patches on the GPS face.
The cable is a 2 wire one.
The pin, which has a spring behind it;
This one T1290642 is from Rocket III Roadsters 2010 to March 2013.
The pin is built into it, and the contacts the pin rotates around on are inside in the unit.
The cable is a 3 wire.
It is no longer available from Triumph as it was superseded by the next one far below.
When Triumph fixed the Roadster GPS fault in March 2013, the 3 wire new style GPS above was superseded by a 4 wire GPS that looks the same except has a 4 wire cable on it.
The 4 wire GPS is T1292057 below, which was the final GPS for the Roadster.
This looks similar to the 3 wire one above, i.e. the pin is built into the GPS, but a little difference in the face design, and obviously the amount of wires and the plug top.
N.B. if you have a 2010-2013 Roadster, you also need T1290666 which is an adapter fly lead to connect the GPS to 2010-13 Roadsters, because 2010-2013 main harnesses have the matching 3 pin oval plug as T1290642 above has. But you can buy T1296589, which is a kit that contains T1292057 (final Roadster GPS), T1290666 (adapter fly lead) and T3600267 (o-ring for the GPS) instead of buying separately.