Subs on factory HU

Subs on factory HU

I ran all my wires, and my subs are hooked up. I slipped the remote wire in the blue wire in the harnes so the amp would cut off with my HU. That all works fine, but I've tried numerous ways to hook my RCA cables up but nothing works. I don't want to splice the wire harness, so I tried using the terminals on my rear speakers with a RCA adapter, but it will work for one second and the the protection LED on my amp comes on and it cuts off. It only comes on after I put the RCA cables in. I have them grounded and everything. So does any one have any ideas (besides buying a new HU at the time)? Any help would be appreciated. Thanks

Firstly, don't ground your RCA cables. The ouput of the stock head unit is a high power output. Essentially for each speaker the two wires are amplified by power amplifiers running out of phase. This allows you to double the RMS voltage, which quadruples the RMS power. Neither speaker wire is a ground. If you ground the RCA cables you will damage the head unit.

Secondly, are you plugging the RCA cables into RCA jacks on the amplifier? If so, make sure that these inputs are true differential inputs and are not grounded. Also, the voltage levels generated by the head unit are considerably higher that the line level standard (RCA). You will overdrive the amplifier and it will probably cut out.

What amplifier are you using? Does it have speaker level inputs?

I bought a RCA adapter kit. It has 6 wires on one side and 2 (left and right speaker)rca inputs on the other side. The 6 wires are + and - left speaker, + and - right speaker, and the two grounds. I didn't know what wires were the rear left and right + and - on the harness plus I didn't want to splice them, so I put the adapter on the rear speakers themselves and grounded the 2 grounds on screws in the trunk. It was some harness from circuit city. To give you an idea what I'm talking about http://www.installer.com/hilo/ it looks like P35 (3rd from the top). Thanks for helpin me out. I better get some sleep cause I have to pull a 15 hour shift at work tomorrow. So I'll check this at about 11 pm tommorow if you have any ideas. Peace

What make and model is your adapter kit?

Finally....

After a month of planning, I finally got my system installed. The adapter worked, but it wouldn't work if you wanted to use it in the back. You have to hook it up directly to the harness the goes into the HU. I did it without splicing any wires cause I'm a little over cautious about the whole car warranty stuff. But it sounds pretty good and I'm happy. If anyone wants details on whats needed and how to do it, I'll be glad to help. Thanks for the help

One more thing

Is there any other way besides running the wires down the other side to get rid of the engine whine? Cause it took me to long to do, but if its the only way I'll rewire. Thanks in advance for any suggestions

Hey JuicyJ, would you mind posting a DIY on how you installed that adapter. It will be much appreciated. I'm saving up for a nice MP3 HU, in the meantime if this allows me to hook up my amps and subs to the factory HU, might as well take advantage of that.