Depends on the chip and who installed it mate. i installed mine in the glove box and ran the cables into the engine bay. If i was you i would start at the fuel pump harness and trace it back from there. It might be obvious with a wire tapped into the harness or it might just have a plug that sits between the pump and the oem harness.
there may also be a wire tapped into the throttle position sensor that you could trace back to the chip, again it depends on the pump.
But as i said, it could be anywhere really. depends on how the person wanted the final thing to look, factory look, didn't care, or wanted it unknown that it was even there.
Best of luck but mate.