Final fix for this so you don't have to hunt for the fuse. I bought an OBD extension cable and added a switch to the pin 16 wire. Using an external power supply to the Tech 2 using the plug hole on the cable near the CANdi unit, it works flawlessly.
Funny thing though, with the external power connected (I used a lithium booster pack), it worked perfectly whether the switch was on or off, as if using the external power plug cuts off the OBD vehicle power. It's funny because it didn't work before. Oh well, either way, I have the switch.