I see this repeated frequently on the forum, so I decided to write up an how-to on the easiest way to wire the 4 factory location speakers (Mids/Highs) in your cobalt to a 4 channel amplifier
I worked as a car audio installer for over 14 years, and have done this method more times than I can count, with amplifiers up to 500 watts/channel with no problems, although I'm sure I will get the usual "but the wire is not heavy enough for the amplifier power" arguement. Use your own judgement, but I can tell you from experence, that it is not a problem. After all, look at the tinsel leads on the speaker, they are usually 18ga or smaller, if they can handle the power, so can the factory wiring.
this will of course, also work with the factory speakers as well, but a high powered amp will likely destroy the cheap factory speakers, so a speaker replacement is recommended
this method will not work with the factory amplified systems, you will have to wire to the front speakers themselves (or to the amplifier location, which is under the steering wheel, I think it would be just as easy to wire to the speakers themselves)
If you are not sure if you have the factory amplifier, here are some tips:
do you have the factory sub...well then you have the factory amplifier....
when you pull out the radio...plug in the adapter harness before making the modification below, get any one of the speaker leads...say the Gray (+) Gray/black (-) Right front lead, and touch the wires + and - to a 9 volt battery...if the speaker makes a pop sound, you do not have a factory amplified system, and this method will work for you
Step 1:
remove your radio of course, this method works with an aftermarket radio, but will also work if you use the factory radio, and cut the speaker leads and wire a line output converter to the radio side for the RCA output to the amplifier
on the adapter harness, you will have the ( 8 ) speaker input leads
Gray (+) Gray/black (-) Right front
White (+) White/black (-) Left front
Violet (+) Violet/black (-) Right Rear
Green (+) Green/Black (-) Left Rear
connect the wires as follows:
Gray (+) to Violet (+)
Gray/Black (-) to Violet/Black (-)
White (+) to Green (+)
White/Black (-) to Green/Black (-)
the end result should look something like this:
I have pictured a PAC audio C2R-GM11
of course, you would heatshrink, tape, or otherwise insulate these wires
you have now created a circuit in which your rear speaker leads are connected directly to the front speaker leads that are already running throughout the car (do you get where I am going now?)
you would not connect the speaker outputs from the radio, isolate those wires to keep them from touching each other or grounding out
Run a single conductor wire (usually at least 16ga) from the amp turn on lead of your radio (usually dark blue) or if you still have a factory radio, find the power antenna lead (some will also tie to an accessory fuse in the fuse box)
run the RCA cables and the remote turn on wire into the trunk
Mount your 4 channel amplifier somewhere in the trunk of your car... I put mine right on the rear deck
Run the power wire with fuse directly from the + terminal of your battery in the trunk
Run the ground cable from your amplifier to a bolt on the chassis, but be sure to clean off all paint where the eyelet will mount to the chassis for a good ground connection
connect the previously run remote turn on wire to the remote lead on the amplfier, and connect the RCA's to the input of the amplifier
Remove the speaker leads from the rear speakers, you can then either cut the connector, or use an adapter harness such as this:
Metra Part # 72-4568 | GM wire harness | Metra Online
Connect the body side of the rear speaker wires to the front leads of the amplifier, the left rear connection is now the left front, right rear is now right front
Connect the rear output leads from your amplifier directly to the rear speakers
start the car, turn on the radio, and adjust the gain controls of the amplifier
***I say to start the car for a couple reasons, firstly, if you have engine noise through the speakers when the car is running, it can be removed many times by turning down the gains on the amplifier, if this does not eliminate it, check your ground wire on your amplifier, a bad ground will often show itself with amp noise, if these fixes do not work, try a ground loop isolator, such as this:
Amazon.com: 4 Channel Ground Loop Isolator: Computers & Accessories
also, this can take quite a while to get the sound right where you want it, if the car is running, you won't kill the battery, but be sure whereever you are doing this is well ventilated from exhaust gasses
re-install the radio, and enjoy having much cleaner, louder mids and highs!
I worked as a car audio installer for over 14 years, and have done this method more times than I can count, with amplifiers up to 500 watts/channel with no problems, although I'm sure I will get the usual "but the wire is not heavy enough for the amplifier power" arguement. Use your own judgement, but I can tell you from experence, that it is not a problem. After all, look at the tinsel leads on the speaker, they are usually 18ga or smaller, if they can handle the power, so can the factory wiring.
this will of course, also work with the factory speakers as well, but a high powered amp will likely destroy the cheap factory speakers, so a speaker replacement is recommended
this method will not work with the factory amplified systems, you will have to wire to the front speakers themselves (or to the amplifier location, which is under the steering wheel, I think it would be just as easy to wire to the speakers themselves)
If you are not sure if you have the factory amplifier, here are some tips:
do you have the factory sub...well then you have the factory amplifier....
when you pull out the radio...plug in the adapter harness before making the modification below, get any one of the speaker leads...say the Gray (+) Gray/black (-) Right front lead, and touch the wires + and - to a 9 volt battery...if the speaker makes a pop sound, you do not have a factory amplified system, and this method will work for you
Step 1:
remove your radio of course, this method works with an aftermarket radio, but will also work if you use the factory radio, and cut the speaker leads and wire a line output converter to the radio side for the RCA output to the amplifier
on the adapter harness, you will have the ( 8 ) speaker input leads
Gray (+) Gray/black (-) Right front
White (+) White/black (-) Left front
Violet (+) Violet/black (-) Right Rear
Green (+) Green/Black (-) Left Rear
connect the wires as follows:
Gray (+) to Violet (+)
Gray/Black (-) to Violet/Black (-)
White (+) to Green (+)
White/Black (-) to Green/Black (-)
the end result should look something like this:
I have pictured a PAC audio C2R-GM11
of course, you would heatshrink, tape, or otherwise insulate these wires
you have now created a circuit in which your rear speaker leads are connected directly to the front speaker leads that are already running throughout the car (do you get where I am going now?)
you would not connect the speaker outputs from the radio, isolate those wires to keep them from touching each other or grounding out
Run a single conductor wire (usually at least 16ga) from the amp turn on lead of your radio (usually dark blue) or if you still have a factory radio, find the power antenna lead (some will also tie to an accessory fuse in the fuse box)
run the RCA cables and the remote turn on wire into the trunk
Mount your 4 channel amplifier somewhere in the trunk of your car... I put mine right on the rear deck
Run the power wire with fuse directly from the + terminal of your battery in the trunk
Run the ground cable from your amplifier to a bolt on the chassis, but be sure to clean off all paint where the eyelet will mount to the chassis for a good ground connection
connect the previously run remote turn on wire to the remote lead on the amplfier, and connect the RCA's to the input of the amplifier
Remove the speaker leads from the rear speakers, you can then either cut the connector, or use an adapter harness such as this:
Metra Part # 72-4568 | GM wire harness | Metra Online
Connect the body side of the rear speaker wires to the front leads of the amplifier, the left rear connection is now the left front, right rear is now right front
Connect the rear output leads from your amplifier directly to the rear speakers
start the car, turn on the radio, and adjust the gain controls of the amplifier
***I say to start the car for a couple reasons, firstly, if you have engine noise through the speakers when the car is running, it can be removed many times by turning down the gains on the amplifier, if this does not eliminate it, check your ground wire on your amplifier, a bad ground will often show itself with amp noise, if these fixes do not work, try a ground loop isolator, such as this:
Amazon.com: 4 Channel Ground Loop Isolator: Computers & Accessories
also, this can take quite a while to get the sound right where you want it, if the car is running, you won't kill the battery, but be sure whereever you are doing this is well ventilated from exhaust gasses
re-install the radio, and enjoy having much cleaner, louder mids and highs!