one bass shaker two signals

We are going to be installing some bass shakers in our car. The one on the drivers side needs to have two signals going to it; the regular signal from the radio, and a signal from an auxiliary source (see graphic below). How do we isolate these two signals so that the radio signal doesn't effect the auxiliary source, and the auxiliary signal doesn't effect the radio source? I'm guessing a diode or maybe a relay would work, but if that's true then how would I wire it?

You can not use a diode in this application.  I am not clear on what you are wanting to do.  Which one of the souces do you want to have priority over the other?

The stereo would be normally on, BUT when the auxiliary was turned on it would over ride the stereo signal (stereo would not be heard, auxiliary would).

i am an idiot wrote: Does the aux unit provide a switched 12 volt wire when it is turned on?

No. I'm confused by your diagram. Are those wires power wires going to the amp, or speaker wires? The stereo is obviously stereo, but the aux is a MONO amp.

Looking at it I'm guessing that one relay is for the negative speaker signal, and the other relay is for the positive speaker signal? ...and those wires are the speaker output wires for the mono amp, and the left side speaker wires for the stereo, right?

angelars wrote: Looking at it I'm guessing that one relay is for the negative speaker signal, and the other relay is for the positive speaker signal? ...and those wires are the speaker output wires for the mono amp, and the left side speaker wires for the stereo, right?

You are correct.