| Wired For Sound 2004 Chevy Blazer ZR2 |
| December 2004 |
These types of projects usually start out innocently enough. I bought a new Chevy Blazer that came with a fancy in-dash
6-disc CD changer, but no auxiliary input for my MP3 player. I am wholly opposed to carrying stacks of CD's with me in
my vehicle, so Plan A was to use an adapter that plugs into an unused port on the back of the head unit, the same port
that's used for satellite radio and other remote sound devices. My Blazer didn't come with any external audio devices, so
I ordered up a Soundgate adapter. That's all fine and good, but I figured why not go a step further and add a Kenwood
KAC-8401 4-channel amplifier and 3 pairs of speakers to upgrade the stockers? Now we're talking. And while I was at it,
I'd add an Infinity BassLink powered subwoofer to pump out some bass.
Plan A got trashed when the Soundgate adapter didn't work. Never did figure out exactly why, but the company's tech
support guessed that since my vehicle didn't come with any external audio devices, the auxiliary input might not have
been set up to work at all (the head unit wouldn't detect the auxiliary input).
So I moved on to Plan B, which was this: a Sony CDX-F7700 head unit with its own auxiliary input. I installed it with the
Infinity subwoofer and the three pairs of aftermarket speakers (the Kenwood amp was to be eBay'ed, thanks to
ridiculous mail-order restocking charges). Worked fine and sounded pretty good until I realized that when the door and
dash speakers are wired together in parallel, the ohms went from 4 to 2. Not good for the head unit...fortunately I didn't
push it too hard. I tried running the dash speakers separately, then the door speakers, but it didn't sound as good as
when all 6 speakers were going at once. So I moved on to Plan C.
Plan C was to use the Kenwood amp to power all 3 pairs of speakers. Its four channels are capable of handling 2-ohm
loads, and it pumps out 60 watts RMS versus the Sony's 23 watts RMS. But where to mount the amp? It was too big to fit
under any of the seats, and I didn't want it lying in plain view of would-be thieves (although the Sony head unit and
Infinity sub kinda make that a moot point). Also, I didn't want to use up any more cargo space in the back of the Blazer.
I'd heard of guys putting amps in the small storage areas behind the front seats, so that's what I did. It wasn't easy and it
took a long friggin' time, but here's how it went.
6-disc CD changer, but no auxiliary input for my MP3 player. I am wholly opposed to carrying stacks of CD's with me in
my vehicle, so Plan A was to use an adapter that plugs into an unused port on the back of the head unit, the same port
that's used for satellite radio and other remote sound devices. My Blazer didn't come with any external audio devices, so
I ordered up a Soundgate adapter. That's all fine and good, but I figured why not go a step further and add a Kenwood
KAC-8401 4-channel amplifier and 3 pairs of speakers to upgrade the stockers? Now we're talking. And while I was at it,
I'd add an Infinity BassLink powered subwoofer to pump out some bass.
Plan A got trashed when the Soundgate adapter didn't work. Never did figure out exactly why, but the company's tech
support guessed that since my vehicle didn't come with any external audio devices, the auxiliary input might not have
been set up to work at all (the head unit wouldn't detect the auxiliary input).
So I moved on to Plan B, which was this: a Sony CDX-F7700 head unit with its own auxiliary input. I installed it with the
Infinity subwoofer and the three pairs of aftermarket speakers (the Kenwood amp was to be eBay'ed, thanks to
ridiculous mail-order restocking charges). Worked fine and sounded pretty good until I realized that when the door and
dash speakers are wired together in parallel, the ohms went from 4 to 2. Not good for the head unit...fortunately I didn't
push it too hard. I tried running the dash speakers separately, then the door speakers, but it didn't sound as good as
when all 6 speakers were going at once. So I moved on to Plan C.
Plan C was to use the Kenwood amp to power all 3 pairs of speakers. Its four channels are capable of handling 2-ohm
loads, and it pumps out 60 watts RMS versus the Sony's 23 watts RMS. But where to mount the amp? It was too big to fit
under any of the seats, and I didn't want it lying in plain view of would-be thieves (although the Sony head unit and
Infinity sub kinda make that a moot point). Also, I didn't want to use up any more cargo space in the back of the Blazer.
I'd heard of guys putting amps in the small storage areas behind the front seats, so that's what I did. It wasn't easy and it
took a long friggin' time, but here's how it went.
To start with, I removed the rear passenger seat (six 18mm bolts;
deep socket required) and the lower interior panel. Not too hard.
deep socket required) and the lower interior panel. Not too hard.
| --Amp goes here-- |
Naturally, the wiring is the worst part of
the job. GM actually helped out a bit by
placing the carpet overlap under the
rear seats (above, upper right in photo).
It was pretty easy to run the speaker
wires and RCA cables across to the
driver's side, where all the audio cables
were run (power wires run on passenger
side).
the job. GM actually helped out a bit by
placing the carpet overlap under the
rear seats (above, upper right in photo).
It was pretty easy to run the speaker
wires and RCA cables across to the
driver's side, where all the audio cables
were run (power wires run on passenger
side).
<----- Hard to believe all these wires fit
inside the dash. I used a Metra
installation kit with the pocket under the
head unit. With the head unit placed
higher in the opening, it gets the rear of
the unit up above the bracket thingie
inside the dash that often gets in the way
(didn't have to whack it off).
inside the dash. I used a Metra
installation kit with the pocket under the
head unit. With the head unit placed
higher in the opening, it gets the rear of
the unit up above the bracket thingie
inside the dash that often gets in the way
(didn't have to whack it off).
With the lower panel removed, now the fun begins.
The gray padding covers an insert that serves as the
small, oddly shaped storage area behind the hinged
door. It is plastic-riveted to the panel and must be
removed.
The gray padding covers an insert that serves as the
small, oddly shaped storage area behind the hinged
door. It is plastic-riveted to the panel and must be
removed.
| <--- more rivets (small, bottom of photo) |
I used a Dremel tool to grind off the rivets. In theory,
with a little help from plastic epoxy the insert is still
usable if I ever want to put it back in (probably won't
happen). Here it is removed from the lower panel.
with a little help from plastic epoxy the insert is still
usable if I ever want to put it back in (probably won't
happen). Here it is removed from the lower panel.
Lower panel without the plastic storage insert. Can
see the access door on the right (view is from the
inside of the panel).
see the access door on the right (view is from the
inside of the panel).
Now, back to the amp. This photo was after
preliminary mounting. The red wire is power for
the Infinity sub; yellow wire on right is the remote
turn-on wire for the sub. I used a Tsunami amp
wiring kit for the Kenwood amp, which includes
the 4-gauge ground wire and the blue 8-gauge
main wire to the battery. It also comes with an
in-line fuse holder and some miscellaneous,
helpful items. The amp isn't a perfect fit, as the
wheel well gets in the way a little. I had to use a
couple of 3/4" nylon spacers to get the amp to
set out a bit. The pro installers (and the Kenwood
instruction manual) often recommend a plate to
mount the amp on, but obviously I didn't do this. I
put rubber washers under the amp mounting
holes to buffer things a bit.
preliminary mounting. The red wire is power for
the Infinity sub; yellow wire on right is the remote
turn-on wire for the sub. I used a Tsunami amp
wiring kit for the Kenwood amp, which includes
the 4-gauge ground wire and the blue 8-gauge
main wire to the battery. It also comes with an
in-line fuse holder and some miscellaneous,
helpful items. The amp isn't a perfect fit, as the
wheel well gets in the way a little. I had to use a
couple of 3/4" nylon spacers to get the amp to
set out a bit. The pro installers (and the Kenwood
instruction manual) often recommend a plate to
mount the amp on, but obviously I didn't do this. I
put rubber washers under the amp mounting
holes to buffer things a bit.
<--- All wired up. Note the duct tape (I love that
stuff)
stuff)
With the lower panel installed. There's still a surprising amount of
space in there...not sure why GM cluttered up so much of it with the
plastic insert (there's an identical space behind the driver's seat.
space in there...not sure why GM cluttered up so much of it with the
plastic insert (there's an identical space behind the driver's seat.
| And finally, my Sony CDX-F7700 head unit (with RCA inputs for my MP3 player): |
| The RCA inputs are screwed into the Metra kit, so there's no fumbling around with patch cords in the dash. Just plug and play! |
Here's the Infinity BassLink installed in
the rear passenger-side cargo area. It
won't make your hood bounce, but it
adds enough bass for me.
the rear passenger-side cargo area. It
won't make your hood bounce, but it
adds enough bass for me.
Passenger side door with panel removed. Note my
stellar duct tape job securing the crossover for the
Infinity Kappa 62.5i speaker. Nobody will ever accuse
me of being a professional installer.
stellar duct tape job securing the crossover for the
Infinity Kappa 62.5i speaker. Nobody will ever accuse
me of being a professional installer.
Here's where I ran the battery wires for the Kenwood
amp (blue 8-gauge) and the Infinity subwoofer (red
10-gauge). This is under the passenger side dash,
where the radio antenna lead comes through the
firewall.
amp (blue 8-gauge) and the Infinity subwoofer (red
10-gauge). This is under the passenger side dash,
where the radio antenna lead comes through the
firewall.
Here's how I mounted one of the two inline fuse holders. The
white plastic is the coolant reservoir. Just a flat piece of metal
with a few holes drilled (yeah, I know...I need a distribution
block).
white plastic is the coolant reservoir. Just a flat piece of metal
with a few holes drilled (yeah, I know...I need a distribution
block).
This was my first major sound installation, and it was kinda fun. Along with the amp and head unit, I'm running Pioneer
4x6 plates in the dash, Infinity Kappa's (2-way) in the doors, Infinity 6x9 Reference's (2-way) in the rear, along with the
Infinity BassLink powered sub. It won't wake up the neighbors, but it's good enough for me.
4x6 plates in the dash, Infinity Kappa's (2-way) in the doors, Infinity 6x9 Reference's (2-way) in the rear, along with the
Infinity BassLink powered sub. It won't wake up the neighbors, but it's good enough for me.
Update March 2005
Well, I finally got around to installing the PAC SWI-X that's been sitting in its package for about two months. This
device allows an aftermarket head unit to be operated by the steering wheel controls. The concept is pretty simple - it
takes the signals from the steering wheel controls and matches them up with IR signals from the Sony remote control.
So it's basically a learning remote. Installation is a little complicated to figure out at first, but eventually I figured it out.
To start with, you need to have the radio out of the dash, so installing the SWI-X while you're doing the head unit install
works better. Step 1 is to figure out which wires in the factory harness are responsible for steering wheel controls. The
Blazer uses a GM24 wiring harness, as identified in the Vehicle Connector Chart in the PAC instructions. In the Vehicle
Application Guide, the location of the steering wheel control wires are listed as pins A6 and A7:
Well, I finally got around to installing the PAC SWI-X that's been sitting in its package for about two months. This
device allows an aftermarket head unit to be operated by the steering wheel controls. The concept is pretty simple - it
takes the signals from the steering wheel controls and matches them up with IR signals from the Sony remote control.
So it's basically a learning remote. Installation is a little complicated to figure out at first, but eventually I figured it out.
To start with, you need to have the radio out of the dash, so installing the SWI-X while you're doing the head unit install
works better. Step 1 is to figure out which wires in the factory harness are responsible for steering wheel controls. The
Blazer uses a GM24 wiring harness, as identified in the Vehicle Connector Chart in the PAC instructions. In the Vehicle
Application Guide, the location of the steering wheel control wires are listed as pins A6 and A7:
I like this setup because it allows easy access in case I need
to re-program the unit. I drilled two holes in the plastic CD tray
insert (easily removable with just two Phillips head screws), a
bigger one for the group of wires on the right side of the unit,
and a smaller hole for the IR emitter wire coming out of the left
side of the unit. I ran the wires straight down the center of the
console and up through the back of the dash. Under the
plastic insert seen here is a perfect place to hook up the
ground wire. There's a couple of nuts on studs that secure
part of the center console. Excellent grounding.
to re-program the unit. I drilled two holes in the plastic CD tray
insert (easily removable with just two Phillips head screws), a
bigger one for the group of wires on the right side of the unit,
and a smaller hole for the IR emitter wire coming out of the left
side of the unit. I ran the wires straight down the center of the
console and up through the back of the dash. Under the
plastic insert seen here is a perfect place to hook up the
ground wire. There's a couple of nuts on studs that secure
part of the center console. Excellent grounding.
Look closely and you'll see where I mounted the IR emitter. It
needs an unobstructed line of sight to the IR receiver on the
head unit. The Sony unit receives its signals on the right side
of the face, so I mounted the IR emitter on the right side of
the center console.
The best part about the SWI-X is that you can make each
steering wheel control do anything you want (within the limits
of the head unit's remote control). If you want the volume
controls on the steering wheel to scan for radio stations,
make it so. Overall, a nice little gadget.
Update Summer 2006
Sometime during the winter months I started noticing random
static and an occasional odd switch from CD to AUX or the
needs an unobstructed line of sight to the IR receiver on the
head unit. The Sony unit receives its signals on the right side
of the face, so I mounted the IR emitter on the right side of
the center console.
The best part about the SWI-X is that you can make each
steering wheel control do anything you want (within the limits
of the head unit's remote control). If you want the volume
controls on the steering wheel to scan for radio stations,
make it so. Overall, a nice little gadget.
Update Summer 2006
Sometime during the winter months I started noticing random
static and an occasional odd switch from CD to AUX or the
whole unit would shut itself off. While checking for bad wires throughout the vehicle (no easy task), I noticed that the
static returned whenever I bumped the center console. I traced the static to a loose ground wire for the SWI-X. I'd
attached the ground wire on a stud underneath the console, and the nut fastening the stud (and ground wire) had come
loose. Took me about 10 seconds to fix and I've had no other problems since.
Update April 2007
With the addition of train horns in the Blazer, yet another fused power wire was needed. Now with 3 wires connected
directly to the battery (power amp, subwoofer amp and air compressor), it was time for a fused distribution block. I
picked up a 4-position AGU power fused distribution block from Lightning Audio. Much, much cleaner!
static returned whenever I bumped the center console. I traced the static to a loose ground wire for the SWI-X. I'd
attached the ground wire on a stud underneath the console, and the nut fastening the stud (and ground wire) had come
loose. Took me about 10 seconds to fix and I've had no other problems since.
Update April 2007
With the addition of train horns in the Blazer, yet another fused power wire was needed. Now with 3 wires connected
directly to the battery (power amp, subwoofer amp and air compressor), it was time for a fused distribution block. I
picked up a 4-position AGU power fused distribution block from Lightning Audio. Much, much cleaner!
Pin A7 is a blue wire that carries the steering wheel control
signals. Pin A6 is green wire that is the 12V power wire which
gives the steering wheel controls the juice needed to operate.
The Crutchfield wiring harness I got for the Sony head unit
doesn't supply power to Pin A6. So I cut the green wire and
hooked it into the switched 12V main power wire. That way,
the steering wheel controls got their 12 volts. I also cut the
blue wire and connected it to a longer wire that goes to the
SWI-X unit, so that it could receive signals from the steering
wheel controls. It gets a little confusing because the SWI-X
uses a green wire to receive steering wheel controls, whereas
the green wire coming from the steering wheel is actually the
power wire. Also required was a separate power wire going to
the SWI-X so that it can operate. I mounted the unit inside the
CD holder console like this:
signals. Pin A6 is green wire that is the 12V power wire which
gives the steering wheel controls the juice needed to operate.
The Crutchfield wiring harness I got for the Sony head unit
doesn't supply power to Pin A6. So I cut the green wire and
hooked it into the switched 12V main power wire. That way,
the steering wheel controls got their 12 volts. I also cut the
blue wire and connected it to a longer wire that goes to the
SWI-X unit, so that it could receive signals from the steering
wheel controls. It gets a little confusing because the SWI-X
uses a green wire to receive steering wheel controls, whereas
the green wire coming from the steering wheel is actually the
power wire. Also required was a separate power wire going to
the SWI-X so that it can operate. I mounted the unit inside the
CD holder console like this:
Plastic rivet --->
Updated April 2007
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