[Vivaro] Light keeps blowing.

[Typhoon]

Have absolutely no idea what to check to work out the cause of this so any ideas welcome.
My O/S rear light on my Vauxhall Vivaro keeps blowing and I've no idea why. I've changed the bulb about 4 times and they all keep blowing to the point the bulb is smashing.
There is no liquid/water damage within the unit.
Cheers.