I'm not sure I understand your question... Do you mean "should I somehow terminate the aux inputs if there's nothing plugged into them?"

No, don't bother. Even if they did pick up noise, you wouldn't hear it unless you switched to the aux inputs from the remote control. Make sure they're covered and/or not touching metal, but other than that you don't need to worry about it.

If you mean "Are the aux inputs noisy when I plug another device into them?", then the answer is also no. They shouldn't be any more noisy than a set of aux inputs on any other car stereo. If you get noise, there are some standard car-stereo noise troubleshooting documents I could link you to.

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Tony Fabris