Hi Bill. While you could use the accessory pin in your flat 7 pin trailer plug, because of the length of wiring required and voltage drop, most vanners now get the much heavier separate cable wired into their vehicle with an isolator so it cuts off when you turn off your vehicle ignition. This cable is typically joined at the coupling using a flat grey Anderson style plug which has heavy contact tabs. Older Avans (eg my 2010 Aliner ), had relatively light cable from a Merit (cig lighter style) plug in the front chassis frame directly to the fridge via underfloor cabling. I replaced mine with the heavy cable and Anderson connector to the trailer coupling so I am running heavy cable all the way to my fridge. It is important to understand that this will only maintain your fridge's existing temp on the 12V setting while on the road and will not appreciably cool a warm fridge.
I would suggest you remove the outside plastic grille vent/ inspection panel at the bottom of your fridge and check the input cable. Mine connects to a screw terminal block on the bottom left hand side of the fridge. Despite the original factory cable being installed, mine was not connected to this terminal block at all! (Friday afternoon at the factory job!) It was only after removing this panel and checking that i realized why mine wasn't working on 12 Volt.
While using a suitable output solar panel through a controller would also work, it will be open to the vagaries of light conditions, but does give you the advantage of power whilst your vehicle is stopped. You could parallel wire to the same input terminal.
All the best with that mate.

Thanks for your comprehensive answer.
Cheers Bill

As in electric trailer brakes? Yes. They have a simple drum brake with electric control set-up so you must have your tow vehicle fitted with an electronic brake controller which is mounted within reach of the driver and enables you to adjust the severity of braking on your Avan.

The early ones did have over-ride brakes but davew is certainly correct on most Avans made this century anyway.

Hi Star.
I am pretty sure they are acrylic (Perspex). There may be a rejuvention product available from auto shops which will help restore their appearance a bit, (often promoted to rejuvenate the appearance of headlights). Most of these change the visual appearance but of course do not eliminate the fine cracks. You may find a local plastic fabricator who has some better advice, but ultimately all plastics degrade.
Ultimately I would look at replacing them. The spares are pretty exy but i notice the small vent covers are a little more affordable here - http://www.avanspareparts.com.au/specials-and-promotions/display/130-vent-lid-only
Cheers - Dave