Hey guys. Wondering if replacement ML sub are just plug in play or should I need to do anything else after swapping a different unit?

Long story short, my ML sub went to crap and I ordered a another used replacement off the fleabay. Same model 86160-0WG70 for an 07 ML equipped LS, and look identical to the original. After finally getting to the damn thing, I swapped in the replacement unit and get nothing, I can't feel the sub moving any air or vibrating at all. I can plug in my old, albeit blown original sub and get feedback and rattle, but nothing with the new unit. The seller then sent me a 2nd replacement, Did the same process just and got the same result - no deceriable increase in bass. Am I missing something or did I just get 2 duds?

Thanks for any input