Hi John
The following is the text of an article I submitted to a "well known caravanning magazine". Hopefully you may find it useful
Mike
Fitting a Fridge Cooling Fan
We can recommend Italy as a holiday destination - beautiful scenery, good food and wine, etc! The down side is the long tow and the heat once there. We can cope with the heat but the caravan fridge struggled to keep its contents cool.
On our return, I investigated fridge cooling fans. Thermostatically controlled fan kits are available for £31 to £46. I felt that I could find a cheaper but equally effective alternative. Thermostatic control I could do without - I know when its hot!
The "kit" I got together is shown in Picture 1 :-
Two 80mm 12 volt fans from Maplin (RG03D - £4-99 each)
A suitable switch and indicator light - I had these already but an illuminated rocker switch can be bought from Maplin for about £2.
About 2m of twin flex, Araldite or similar adhesive, a couple of scotchlock connectors and a couple of spade connectors - again these I had already.
First, a word of caution. This job does not involve the gas or mains electric operation of the fridge: 12 volts won't kill you BUT if you don't know what you're doing you could still do a lot of damage to your caravan. If you don't feel fully competent to tackle this job then don't - or leave it to someone who is. I would also recommend that you disconnect the caravan battery and mains hook-up whilst doing this job just to avoid any chance of short circuits.
The first step is to remove the upper and lower ventilator grills from your caravan - ours is a Bailey Senator (2009) fitted with a Dometic fridge. This is done by sliding the latch at the left hand end of each grill upwards. The grill can then be (carefully) levered out from the left hand end. See picture 2.
The two fans are glued to the inside of the upper ventilator grill and weighted down while the adhesive sets. Picture 3. Thoroughly clean the grill first to ensure good adhesion.
The fans were then wired together and tested to check that the airflow was in the right direction ie blowing out through the grill - if not, swap the connections round. When wired in parallel the fans worked at full speed but I thought were a bit loud so I rewired them in series. The fans ran more slowly but still generated enough airflow and were significantly quieter. The fans are coupled using two pairs of spade connectors to allow the ventilator grill and fans to be removed. Picture 4.
The lower ventilator grill, once removed, gives access to the wires connected to the fridge. A pair of black wires are tagged "nur 12v" (only 12v). One black wire has two thick conductors, the other black wire has two thinner conductors. All four conductors meet at a four-way connector. See picture 5.
The power for the fans must be taken from the supply side of the connector so the fridge may be removed for maintenance if required.
The two thick conductors (orange and black) power the fridge when the car and caravan are coupled up and the car's engine is running. The two thinner conductors (green and white) provide 12v to the fridge for the internal light and are connected through to the caravan's fuse box. It is this pair of wires that will power the cooling fan using scotchlock connectors. See picture 6.
The fans, switch and indicator light are wired as shown in the diagram below.
Routing the supply flex to the switch (and indicator light) and then back to the fans will vary depending on the layout of your caravan and where you choose to mount the switch - mine is mounted on a upper panel inside a kitchen cupboard. Picture 7.
Make sure the flex is away from any heat sources and can't chafe against any sharp edges.
Replace the ventilator grills. Job done!
A return visit to Italy last summer proved their effectiveness!
