Ok here we go:

The basic idea is to first convert your 2 (or 1) RCA plugs coming from the back of your head unit to a single wire (and ground), put it through the switch/slider, and convert it back to RCA plugs.

There might be differences with what you want to do and what I did:
-I have a stereo pre-amp output on my head unit, but the slider only supports mono
-This is probably only good for low frequency signals, anything high-frequency will probably pick up some noise when it goes through the slider. Besides, since you can only do it in mono, it wouldn't be worth sacrificing stereo for.
-You can also hook up the sub on/off switch in line to the amp. You'll now have a control for whether or not you want the sub on AT ALL.

Ok, I'll start by going over every wire coming from the switch/slider, and then briefly talk about the RCAs, the rest'll be up to you.

Grey-ParkingLight(+) if you already have this switch in your car, just leave the grey alone, its the positive trigger for the light inside the switch. It'll come on as backlighting to the switch when the dash lights are on, just like the defroster and fog light buttons.

Black-Ground(-) also easy, but we'll also be hooking the ground from the RCAs into this later...

Pink-Amp-on trigger(+) This is commonly the blue lead from the aftermarket head unit, telling the amp in the trunk to turn on when the radio is on. By interupting it w/ the switch, you can turn your bass completely off, for whatever reason you might want. (This has come in handy for me for listening to Opie and Anthony no bass needed for talk).

White-Output to Amp to turn on (+) This is the output of the previous wire, and should continue on to the power-on connection on your amp.

Ok, break for the RCA part.....

All you have to do is connect the RCA's tip to the signal wire and the sleeve to ground. It'd probably be best to get a 4-pack of female RCA connectors from radio shack and attach them with small foot-long leads to the switch, that way you can disconnect the switch in the future easily.

Purple-BassIn (+) Take the tip of the RCA and connect it to this wire. this is the input to the slider. When the slider is all the way up the amp will get the full signal of whatever is coming from this wire. If you have 2 RCAs (left and right) coming from your head unit, you can combine the tips of both the left and right RCAs, as well as tieing all the grounds to black.

Red-BassOut (+) The same as purple, but now the signal is coming out of the switch and going to whatever RCA cable that leads to the signal input of your amp. If you need to run stereo inputs to your amp (even though your signal is now mono anyway), you can split this wire to both the tip of the left and tip of the right with no problem.

Ok that covers every wire and their function. If you have basic car-audio knowledge you probably won't need to read more than the first sentence for each wire before you get the idea

Questions, comments, and opinions welcome I hope this helps at least someone

This was origionally posted by Jim 86 Bird in the Body and Interior forum.. just thought i would bring it over to this forum..

 

Thanks for doing the leg-work and copying it over to this forum Mike If anyone has questions or comments, let me know.

 

thanks thats exactly what i needed to know. but the switch/slider. i'll have to print that out later

 

these instructions your giving are for the gain slider switch correct? my car is a 184 trans am and it does have the extra 3'' spakers in the rear. my rear round (smaller) speakers dont trun on. i have an aftermarket head unit. but on my dash i have 2 push buttons with a Music note symbol. one reas "off" te other: "on" will this work for me? what exactly do i have?????

 

I found another unorthadox way to wire this switch in.
Blue/white stripe to positive gain wire
RCA signal to neg gain wire.

I'm able to turn on and off, but not able adjust the slider part of the switch.

 

so if i read that correctly. the Auxillary/Amp wire from the back of the head unit goes into the switch, then back to the amp. same with the rcas?

 

Rephrase that a little more thoroughly for me.

I'll rephrase mine too.
The blue/white stripe wire in your radio harness to the positive wire of the switch.

The RCA signal is the one that runs between the RCA's. Connect it to the negative wire of the switch.

 

Thank you for resurrecting this thread, that is exactly what I was looking for (found the slider at the boneyard)