I made my own switched TRE and mouned the switch in the Hump. That way it is out of the weather and easy to get to. I didn't want stuff in the hump to fly around and hit the switch and turn it off, so I bought a locking switch. It is a toggle that you have to pull on radially and then it will allow you to toggle it to the other position. It can't be knocked around. It is not cheap - $9.00 for the switch alone. I mounted it and the attached printed circuit board in a small plastic box. The toggle fits through a hole I drilled in the front of the trunk on the riders left side. The little box fits under the rear cowl between the front and rear seat with the toggle sticking inward toward the rear of the bike. I ran my little harness to the various areas and covered it in a nylon anti chafe covering. This thing is MIL-spec and cost me about $50 for all the materials and chemicals to make my tiny PCB. It is a $50 solution to a $5 problem. I would recommend just cutting the GPS leads and soldering a $.25 resistor in and wrapping it with vinyl electric tape. I NEVER take mine out of TRE mode.
Now having said that and you are still curious how this thing works:
It is wired up with the switch pole attached to the pink wire coming from the connector of the GPS. The wire is cut between the connector and GPS - not the harness side. One of the throws has the other end of the pink wire down to the GPS. The remaining throw is attached to one lead of the 6.8K ohm 1/2 watt resistor. The other resistor lead is connected to the black wire on the GPS to connector cable. I did not cut the black wire. It is needed in both modes - resistor or stock. I just tapped into it for the TRE.
My switch was a double pole version, so I used the second switch pole to illuminate a LED that I mounted under the instruments in the black cowl. It lights up when the toggle is in the TRE position. I took the power for the switch from the ECU lead that controls the fuel pump. As long as the pump is grinding away the LED is lit. It doesn't pull much current at all and will not affect the operation of the fuel pump circuit. So also I get an indicator that the pump is getting power too (might benefit me stuck on the road somewhere?).
