Hi Findlaters,
Depending on the build of the vehicle, it may already have some of the wiring in place for a wired reversing camera.
In general, a 2007 model will have a pre-installed harness, which is configured for a drop down monitor in the cab headlining and a review view camera.
However, you may find that there is the moulding to take the standard monitor is not fitted.
Depending on how you wish to proceed, you have the option of purchasing the original monitor or fitting an aftermarket device, using the same wiring.
Which ever solution you choose, in the centre of the cab headlining (an aperture would need to be cut to access this) the following connections are present:
1) Jack plug providing a 12v supply (Yellow/Red +ve and White/Orange -ve)
2) 2x connections for 12v lights, which were part of the monitor installation moulding. (Each connection carrying Slate/Red (+ve) and White/Orange (-ve) connections
3) An Orange wire terminating in a female terminal, which is 12v +ve when reverse is engaged. (This was used as a trigger by the monitor)
4) A Red Phono / RCA type connector, which is the video feed from the camera
At the rear door side corner, either in the upper locker corner or just behind, is the point where the video feed and power supplies come together, along with a diode assembly. From this point an S-video style cable will route across to the centre of the upper rear section of the
MH, to be fed through to the outside of the upper moulding and to a camera if required.
Again, depending on the solution you choose, you can pick-up these cables to fit a camera.
I hope that helps.
Ash