Since the Mercedes has seperate stop and turn signals and your trailers' are integrated into the same bulb, you will have to get a converter box. You can get one at PEP BOYS.(one of the few parts I'd get there)

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Benzmac:
ASE CERTIFIED MASTER AUTO TECHNICIAN
LEAD TECHNICIAN FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM