Face palm city.
RCAs on the driver side. Unless you have your battery on the driver side somehow? You don't? Okay, RCAs on the driver said.
Whoever told you the other way around is a.) an idiot b.) drives a car with a driver side battery and is still an idiot for not considering the battery could be on either side and defaulting to telling you to run RCAs pass side.
And if the wire you spliced it to is orange or yellow, that's usually a continuous power wire. Check it for voltage and you'll know. Regardless, look for a blue wire. Usually its tagged separately, but regardless, it should be blue. And usually the radio and the wiring harness have a blue wire, so chances are they're hooked together, a continuous power wire shouldnt be "left over" though, its usually used for the radio to keep the settings in memory.
Edit: I just looked it up, I guess if you have a Kenwood or similar, P Cont is your remote wire. My apologies.
