2020 T120 Gps Switched Accessory Power

I was installing my TomTom and did a quick search on the net and there were no posts that I could find on hooking up the power lead for a GPS to a source that was only live with the ignition on. The factory accessory harness under the tank is hot all the time so you risk running the battery down if you forget to turn it off. I thought about hooking it into the headlight circuit inside the headlight bucket but there had to be an easier way.

I had already run a lightning cord from the USB plug under the seat to where my phone mount was on the bars. I had a look and it is a switched circuit that is only live when the ignition is on. I did a quick test by splicing the TomTom power lead to a USB plug and plugging it into a USB charger in the house. It didn't work, even though the TomTom battery is 5.1v the power lead requires 12v. I could run the USB to the micro USB port on the back of the TomTom but then you need to remove the rubber cap and it is not water proof anymore.

So back to square one, I took off the seat to have a look at the wiring to see if I could spot an easy location to get power. There it was in plain site. The factory USB outlet mounted under the seat plugs into the main harness on top of the rear fender. I unclipped the plug from it's mount and unplugged it from the harness. I really didn't want to start cutting into the factory wiring but seen I could easily get into the plug to the USB outlet and tie in there. I removed the pins from the plug on the USB outlet side one at a time so not to mix them up even though you could just check the harness side of the plug to see which went where. I stripped about 3~4 mm of insulation off the ends of the power lead from the GPS and pre-soldered them. Then I removed the fuel tank to run the power lead from the GPS down under the tank through the plastic factory wiring tray. Be sure to check you have no wires pinched when snapping the cover back on the tray if you use this route. I then carefully fed the ends of the GPS lead beside the factory wire through the rubber seal and soldered them to the pin. By pre-soldering the GPS leads it makes them stiff and easier to push through the seal into the pins. When soldering the leads to the pins take care not to use too much solder and plug up the pin making it now unserviceable. I then pushed the pins back into the plastic plug until they locked in place. I plugged the USB plug with my GPS leads back into the wiring harness, tucked the wires neatly away and turned on the ignition. My TomTom turned on as it should and then turned itself back off when I turned the key off. I may put a dab of waterproof grease on a toothpick and put a little dab on where the wires go through the seal into the plug. Probably not needed but gives a bit of extra insurance if it was ever hit with a stream of water when the seat was off.

Here are a couple pics of the final installation, I didn't think to take any pics while I was doing it. For those not familiar with taking pins out of plugs to work on them tread carefully.. I chose to use the USB side of the plug just incase something did mess up I would only have to replace the USB plug and not have to mess with the factory harness. The USB outlet is fed through the fuse box with a 5 amp fuse which is more than enough power for the GPS and a cell phone. The GPS hardly draws any power at all, the wires are pretty thin. The inline fuse you see in the pic under the seat is for the lead for my battery tender and is also used for heated gear.