So the short harness which connects the dash radio harness to the head unit is labled. Alot of these aftermarket short harnesses are labled. Weird thing is, there is no ground wire, but i believe in a different post, I read that there is a ground wire coming from the dash harness in fact i think it is "L-Y" which is the manuals version of saying bLue Yellow. I have a feeelibng the aftermarket short harness is labled wrong or something.

For example, one wire is titled Power Antenna. As far as I know there are no power antennas in evos. (maybe in lancers ??) could this potentially be the ground wire?

Example 2, one wire is labled "Mute". I have no idea wtf that is. So i have my radio grounded to a bracket, but I think that i have a floating ground (too much resistance between the grounding point and tru ground (where the negative battery terminal connects to the chassis).

Here is why i think that ground may not be good. After swapping two different amps, my subwoofer amp makes a beat (similar to a heartbeat) which plays constantly when the radio volume is completely off. Actually that may be a problem with the amps. I tried two of them so maybe its a problem with my Sub RCAs running along the power wire.

So, anyone know abouth te "mute" wire, and the "power anteena wire" ? what are these wires actually?

 

So where should u ground it? I have the same problem. I have mine grounded right on that bolt just below the heater ac controls

 

Mitsubishi's tend to not have a ground wire for their radio. You will just have to ground it to a piece of the car's chassis behind the radio.

 

I'll explain the color of the wires and what they do. In SSL evo's the power antenna is also remote turn on for the infinity system. Mute, is for cell phone input to mute your radio during a call. It's for a hands free system.

For your heartbeat issue, i need more information. What size amp (RMS please not peak power) and what gauge power wire you are running. Also brand name helps. Next, how cheap of RCA's are you using? What kind of head unit is it? Be specific with model numbers and i'll have an answer for you.

The bracket where you grounded is fine. Though my preliminary guess is the head unit's RCA's aren't shielded properly and you are getting noise through them. The second possible is, you have a factory infinity system and you are getting feedback through that.