I have reproduced his e-mail below in full which contains the instructions for making it,thank you David.
Just returned from a sizzling 2 weeks near Paris - Cadiz behaved itself very well I am pleased to say - and so did my fridge cooler.
It is a little regrettable that caravan fridges seem to draw their cooling air from the very hot awning area - I note that Dometic offer a fan with thermostat which I assume fits onto the cooling vanes inside the cover and costs £50! A cheaper version can be made at home for very little money as follows:
- Remove the top vent and measure the rectangular gap.
- Cut a piece of hardboard or thin ply that fits fairly snugly into this gap (corners will need to be radiused and two holes on LHS drilled so the board fits in correctly)
- Obtain a couple of 12v cooling fans from old PC's and fit to the board after cutting the ventilation holes though
- Wire both fans to operate when 12v is supplied to the lead (note the fans should extract air and blow into the awning space)
- drill two 10mm holes about halfway down the shorter sides to allow for thin elastic cord to pass through
- Attach two curtain hooks to the support wooden struts either side of the opening to attach the elastic cord
- Run loose cable into caravan to pick up a 12v supply (tv point?). This lead only needss to be low voltage 'bell wire' - I have already run a 12v supply (using thicker cable of course) direct from the battery, under the floor to just behind the wheel mudguard for just this purpose (or a coolbox - or a tyre pump....)
- The board is positioned and the elastic cord fed through the 10mm holes; a couple of 'spring loaded elastic cord toggles' holds the board in place.
- See photos: Picture 1 shows the board fitted and fans running; Picture 2 shows the board lowered on the straps and the elastic cord attachment points inside opening.
Whist one 3" fan has plenty of air movement, I used two fans as they cost me nothing and I have redundancy if one were to fail.
At night when the temperature in the awning is more acceptable, I remove the board but leave it connected via the shock cords and turn off the fans so its ready for the next hot day. Clearly this is only for use when the awning gets very hot.
Not so elegant as the Dometic 'fit and forget' unit, but cost me nothing which is a bonus!
Kind regards, David