Best I can find that is not micro controlled and does not have a FET on it is BJB ( aka Battery Junction Box / engine compartment fuse panel ) Fuse #54. Looks to be enough room to install an Add-a-Fuse in this slot to trigger a relay.
This is hot in Run and Start positions.
This is the fuse for a few things, but the most notable is the DTR ( Digital Transmission Range Sensor ).
Keep in mind on the 09-10 MY, you do not want to take a chance with a FET controlled circuit, if you have the correct sequence of high current draw operations, the FET will shut down. This includes probing around with a test light.
Micro controlled circuits you would not want to use for add on items either, this part of the SJB ( Smart Junction Box ) is not serviceable, and if damaged would require a net SJB to be installed ( and programmed for your truck options ).