I installed a Piezo electric beeper at the rear of the Prado underneath the body near the LHS bumper. It cost me ~$10 from Jaycar. I made an "L" bracket out of a small piece of Galv. sheet & drilled a 25mm in it to mount the beeper. The beeper has a 12V connection for an intermittent beep. Then I connected a piece of twin flex. to the reversing light wires behind the tail light assembly making the joints with those straight thru connectors. An easy job to do!. However, I wrapped two layers of duct tape over the beeper to quieten it down a bit and also to keep the dust & water out. Also, as a final touch, I bought a small switch to isolate the beeper (for instance when backing the CT in the Caravan ground so as not to disturb everyone). I mounted the switch next to the rear power outlet near the rear door. Sparky