Removing exit vent to access towing electrics on M Class

I am wiring in my new tow bar (2000 ML 270CDi 163) and I need to connect the electrics to the plug that is behind the near side exit
vent. I have removed the bumper and can see where it is, but what is the method for removing the plastic vent without breaking/snapping something?
Can anyone give me any guidance? Cheers
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