Firstly, no such thing. The stereo plugs are generic for almost ALL Nissans in a certain era (they used the same yellow/white plug in all stereos from the late 80's ---> 1995, another stereo plug took over from 1995 --> 2002 (iirc))i used a 240SX wiring harness because they seemed to match up.
Secondly... I've fitted many, many stereos (a lot using the ISO wiring harnesses) but I ALWAYS test the wiring before I connect anything.Everything looked good after the install but the audio is really faint, and my front right speaker isn't getting any audio
I can take a picture of my wiring, and maybe someone can see if I missed something somewhere.
Problem is, that not working speaker may not have anything to do with the new stereo... but it might.
Was the speaker working before the new stereo went in?
Depending where the speaker problem is, continued use of your stereo may end up frying either - that channel OR the stereos entire amp.
You need to find the problem immediately.
It's really hard to guide you with this problem.... if you brought the car to me I'd spend time fault finding and testing wires, but that's something you learn with experience etc... it's very hard to pass on that info over the net.
Take some pics of the wiring and post them up... you never know, it might help!