hey all. i recently purchased a GTA and after much searching figured out how to do this. so i busted out a quick "tech artical" style post. i think i wrote it so anyone can understand it. there are no photos yet. tell me what you think. and if anyone wants the .DOC version (bolded in places and with font formating for ease of reading) let me know, i'll email it to ya.

EDIT* THIS DOES NOT WORK! at least not for me. lower down there is a method of getting the toggle portion to work.



How to wire your factory “GAIN” control in your 82-92 FBODY to work with any aftermarket amplifier

The goal of this article is to enlighten you as to what I feel is the best (not fastest or easiest) way to regain the use of your factory “gain” control switch. These instructions allow you to leave your factory wiring completely unchanged and unmolested. Splicing is only required if you are retrofitting a gain switch into a car that was not originally equipped.

The factory “gain” switch I am referring too was equipped in all Firebird models with the UQ7 “performance sound” option. Many firebirds from 87-92 came with the UQ7 option.


list of tools needed
Socket wrench and 7MM or 9/16” socket.
Electrical Pliers
Soldering gun (recomended)

Supplies
14AWG wire
14-18AWG speaker wire
2 solder type RCA style connectors or small RCA cable
6 14AWG female modular connectors
2 14AWG male modular connectors
1 14AWG wire nut
1 one wire splice (usually blue, allows you to splice a wire without cutting)
Stock “gain” control switch. This can be found in junkyards and on ebay.

Step one:
Using 7MM or 9/16” socket remove all the screws retaining gage bezel to dash, you will also have to remove the passenger side upper kick panel. Remove factory “GAIN” switch; or if not equipped, remove factory block off plate.

Step two:
A: If you are using an RCA cable, cut it in half at the center and strip it. You should now have two wires, one shielded in the center, and unshielded wire wrapping the shielded wire. The shielded wire is your positive (+) wire. It goes to the “nub” in the center of the RCA jack. The unshielded wire is your ground or negative (-) wire. Secure female modular connectors to the ends of the positive (+) leads of both. Secure the ground wires together with wire nut.

B: if you are using the solder style plugs, solder wire leads (leave about 1-2’ slack) on to them. Secure female modular connectors to the ends of both positive (+) leads. Secure the negative (-) leads together with the wire nut.

Step three: cut two lengths of wire the same length as your RCA cables. Secure female modular jacks to one end of both wires

Step four: cut two lengths of wire about 6” long. Secure female modular jacks to one end of both wires and male modular jacks to the other

Step five: look at the back of the switch, the wires should connect as follows. The colors of the wires listed are the color of the leads on the original GM factory plug (if equipped) for ease of understanding.
Top left (red): one of the RCA cable (+) leads, This RCA out goes to your amplifier.

Top middle (purple): other RCA cable (+) leads, this RCA in comes from the “preout” on your deck.

Top right (black): one of your 6” wires. The male end can plug into the same location on the factory gain switch plug (if your car was originally equipped) or to any other good ground behind the dash. This is the ground for the light inside the switch

Bottom left (grey): one of your 6” wires. The male end can plug into the same location on the factory “gain” switch plug (if equipped) or to the grey wire on any other switch behind the dash. This is the (+) for the light inside the switch. Without this the switch will still work, but will not light up with everything else.

Bottom middle (pink): one of the long wires. This goes to the remote power out on your deck (usually a blue wire). This wire allows the amp to come on whenever the deck is powered on. Attaching this wire allows the toggle on/off button to completely turn of your amplifier.

Bottom right (white): the other long wire. This goes to the remote power lead on your amplifier.

Step 6: after testing the switch with the deck powered on, plug switch back into factory location and reattach with screws. Reattach dash. Admire job well done…

 

Good article

 

i used a post of yours from like... 3 yrs ago as a starting point. i think it was originaly in "apperence and detailing"

 

so, despite my awsome wiring i never got this to work. i descovered a few weeks ago that my switch was broken. after a brief search i called house of camaro and they said that they only had two left as a result of an article on TGO about them...... as i doubt it was this "article" i am wondering if anyone knows what he is talking about. i would love to read this article if anyone has a link. thanks.

also a re-write of this is in the works with better instructions once i get the system working... turns out there is a WAAYYY better and more simple way to do it on a car originally eqiped with UQ7, these are still pretty good for a retrofit. once i get my new one there may also be a "how to fix your broken GAIN slider switch" article in the future. if i can figure out how to fix it that is

 

Note that depending on the design of the HU you will loose considerable (or all) stereo separation doing it this way (if I read it right).

 

yeah, another option is to just run one channel to the sub.

 

I should have clarified. This can affect other outputs as well. Say your HU has only one set of pre-amp outputs (front). If you take the two pre-amp outputs and tie them together you can loose separation even from the (front) speaker level outputs. This all depends on the HU and how they handle the pre-amp stuff...

 

i should also clarify, maybe i am using the wrong term, but by ”one channel" i meant RIGHT/REAR or LEFT/REAR.

anyway, i went back at it today since i received my new switch from house of Camaro. no matter how i wire it i get a nasty buzz through the sub. even with the car off and ignition in ACC position (i have an 88+). the buzz was inaudible with the speakers on any higher then volume level two (with 35 being the average listening volume, 50 being "blasting" and 15 being the volume you would set if you were talking to someone)..

while i had the switch hooked up i also came to the conclusion that the UQ7 switch barley changed the gain level. not the kind of change i was hoping for. i guess i will just continue to use the pre-out adjustment on my deck. the toggle however still works. that is quite useful, when i am nearing my destination i can turn my bass off completely as not to call attention to my car. it is also nice to shut it off at lights so i don't bother other road users.

if you wish to retain the toggle use of your UQ7 gain switch: you do not need to cut ANY of your factory wiring, all you need is one of those blue crimp-splicers you snap on to an existing wire that allow you to tap off of it.

step 1: pull your passenger side hush panel and the lower dash trim (the piece that will say "performance suspension" if you have WS6) and remove your factory amplifier, it is the silver box (~6"X6"X1") on the far left. see image below

step 2: unplug the connector from the factory amplifier, and locate the white wire. attach a blue splicer thing (pictured) to the white wire. insert another wire (preferably blue, for simplification) in the splicer and crimp down with pliers, snap closed.

step 3: connect wire you attached to the white wire to your amplifiers "remote" wire. usually this is a blue or blue/white wire. test the switch. now it should be a toggle for your amp(s). if it is not proceed to step 4. if it is skip to step 5.

step 4:
a: with a test light check to see that the white wire has power when toggle switch is in ON position. if it does re-do your splice and re-test. if it does not proceed to b:

b: remove your radio. locate the pink wire. IF you are using an adapter harness to connect your after market deck to your factory harness or are using a stock radio this wire should be attached to your factory harness. IF you are ding it the custom way, and cut out your original harness in favor of doing it yourself this wire should be connected to the "remote power" lead on your deck (usually blue). turn your head unit on and test this wire with a test light, if it is hot proceed to step c: if it is not figure out why not.

c: remove your gage trim bezzle, or for digital cluster cars the right most portion of the guage trim. locate harness for gain switch. plug it back in. if it is already plugged in turn on your deck and test the pink wire with a test light. it should be hot. if it is not and it is hot behind your deck you have a short. provided that wire is hot turn the gain switch "ON" and test the white wire. if it is not hot you have a bad switch. good luck finding a replacement.

d: provided you now have a working switch, or have replaced your defective unit with a working one, put your dash back together and re-install your radio/head unit.


step 5: tuck the factory amp connector back up behind the dash, and if desired reinstall the factory amplifier. for the love of thirdgens DO NOT RECONNECT THE AMPLIFIER! if it was plugged in before it is probably burnt up inside by now, but why chance it. leave it unplugged.

step 6: reinstall hush panel and lower dash trim. drive away.

 

Others have gotten it to work with out noise? Wander what was going on, bad ground? That wound give you the noise and could account for lack of control over the "gain" (technically attenuation doing it this way).

 

first time i have read back over this post since i last posted... have others gotten this to work? if so post up with a simple how to. perhaps my "new" switch is also broken.