Would there be any compatibilty issues installing a headunit from a 2000 ITR into a 1995 LS.

I've sold my headunit, and the customer is having difficulty installing it. Says that it doesn't seem to have power. And then when he plugs his stock tape deck headunit in it works.

And I am 100% sure my headunit works, aside from considering that it got damaged from shipping, would there be anything to troubleshoot? Are the pin layouts the same from a 2000 ITR to a 1995 LS.

Thanks