Wired my sub and amp up, but doesn't work?

I have an a/d/s sub with a built in amp that my dad gave me from his old benz that i wired up. I’m pretty sure i did it all correctly, but when i turn on the radio, all i hear is buzzing from the sub.

I wired the power to the pos terminal of my battery (located in the trunk)
Grounded the wire to the chassis (sanded the paint first)
Wired the remote wire to the blue remote wire on the back of my deck (alpine)
And plugged in the RCA cables from the back of the sub to the back of the deck.

Pretty simple stuff i assume, but it still doesn’t work. Could the sub/amp be bad?

sounds like what i would have done. nothing wrong there. test and make sure (with a voltmeter) you are getting a full 12.something volts. the black and red wire. if so, check the amp turn on wire, same idea, with the black and blue. make sure the car is on. if that is good, get an rca speaker (20 bucks radio shack) and plug your rca’s in it separately. if both rca’s are good. then it is def the amp and/or speakers. find a speaker (any) and hook it up the amp and see if it works. if it does, then the speakers are blown. if it doesnt, the amp is blown. how old is the setup? how long was it used? was it stored and/or not used in awhile?

So u have a sub with a built in amp. Check and make sure the amp is not switched to high power input (gets its signal from the readio’s speaker wire outputs) It needs to be on low power input in order for rca’s to work.
There might not be a switch, but a couple of wires that are the same color that needs to be looped together, they might be short wires at the plug that goes into the amp.