Make sure your mains hook up socket is sealed...

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If you have a hook up socket check thatits weatherproof. While having a few days away camping last week I got talking to another Bongo owner and he reckoned while he was checking the underseal he found a big hole behind the drivers side rear wheel, below where his hook up socket is fitted. He also found the square metal cut out inside the hole, whoever had fitted the socket had just pushed the cutout inside the wing and had not sealed the fitting. Might be worth a check if you have hook up.