For future reference i thought i would help out other 05+ Taco owners. You can tap the reverse wire behind the drivers side kick panel. Its the red and white wire coming out of the second from the bottom plug.
I have my gps antenna in my Taco stuck to the metal support brace that runs under the dash. If you drop down the glove box you can see a nice open place to stick it in the far right corner, my reception is fine and the antenna is not visible.
There is two ways to reset the unit, i would try both.
1. With engine/ignition switch OFF, press and hold reset for a couple of seconds
2. With engine/ignition switch ON, press and hold reset for a couple of seconds