Part 3: Making It All Work
About 75% of the total project is mounting the hardware. The rest is
routing the air lines and wiring it all up. My first task was connecting
the line from the compressor to the tank. While it is not absolutely
critical to have the compressor close to the tank, it sure does make
it easy to connect the braided steel air line. Once I had air going into
the tank, I threaded a compression fitting for the 5/16" air line into
the air tank and quickly discovered I would need to get some
90-degree connectors. The nylon air hose just doesn't have a very
tight bending radius. I needed 90-degree connectors for both the air
line to the horns, and the air intake line for the compressor. Without
the angled connectors, the air line tended to get in the way of the
drive shaft.
Routing the line along the inside of the frame rail is relatively easy.
Routing it from the frame to the engine bay, not as much. For
reasons explained later, I needed the air line to be accessible under
the hood. I routed the line along the inside of the drivers side wheel
well, which requires much care in securing the line. In routing the air
line through this area, it's remarkably easy to let the line rest against
hot engine parts on its way into the engine compartment. During my
initial weekend at the farm mounting the horns, tank and
compressor, I could smell something getting hot when I popped the
hood after driving home. Fortunately I figured out what happened
before testing the system, and even more fortunate was my earlier
purchase of an extra 20 feet of 5/16" nylon air line from
McMaster-Carr.
One thing I did differently than most was mount the pressure switch
inside the engine compartment. While the switch appears to be
relatively water resistant, I didn't want it attached directly to the tank
where it could potentially take a beating on the underside of the
vehicle. Plus, it would be one more small-gauge wire to take care in
protecting on its way from the engine bay to the tank. To accomplish
this, I needed to tee into the air line under the hood. The pressure
switch would be connected at the tee and monitor pressure from
that point, rather than directly at the tank. The pressure switch has a
1/8" male connection, so I found a tee at McMaster-Carr with a 1/8"
male connector and two 5/16" compression fittings. A dual-female
1/8" connector from home depot completed the hookup
With the air lines complete, I screwed in a drain cock and a 175 psi
pressure release into the spare ports on the air tank. The remaining
ports will serve as auxiliary air for whatever I can think of that might
be interesting.
Giving the system some electrical juice was the next task. The
compressor needs a direct line from the battery, by way of the
pressure switch (with its internal relay). The Hornblasters.com
instructions outline this pretty well. In between the battery and the
pressure switch is a 40 amp fuse. With the compressor being the
third component in my Blazer needing direct juice from the battery
(the main amp and subwoofer amp for the sound system were the
other two), I decided it was time for a fused distribution block from
Lightning Audio.
The pressure switch needs its owns power source to function, and
this power comes from the ignition wire of your choice. I chose the
power wire for the cruise control module. I also used this to power
the solenoid in the air valve. If wired this way (per the
Hornblasters.com instructions), the pressure switch will only be
functional when the ignition is on, which prevents accidental battery
drain. I went a step further and added a manual switch inside the
cab, just in case I didn't want the compressor running under any
circumstances. This switch is wired between the cruise control
module wire and the pressure switch lead. If the compressor switch
relay can't get any juice, it can't turn on the compressor.
I installed a push button for activation of the solenoid, mounted in
the console just under the headlight switch. The button went where
some optional switch of some sort would have been (fog lights,
maybe?). The wiring harness actually plugs into a plastic housing
on the back side of the console, even though there's nothing there
on the front side. I simply drilled out a hole big enough for the button,
screwed in the button, routed the wires through the dash and
firewall and put the console all back together again.
Again, I took this a step further. I tend to favor my left hand when
steering, so pushing a button with my left hand would require a
quick switch of hands on the steering wheel. The ideal location of a
button switch would be on the shifter, but I couldn't think of a good
way to mount it without calling attention to it. So I added a second
button switch that's more of a hand trigger, complete with a coiled
cord. While driving through the streets of Chicago, I can hold the
trigger switch in my right hand and steer with my left. The second
switch also lets passengers take part in the fun of blasting
unsuspecting drivers and pedestrians.
About 75% of the total project is mounting the hardware. The rest is
routing the air lines and wiring it all up. My first task was connecting
the line from the compressor to the tank. While it is not absolutely
critical to have the compressor close to the tank, it sure does make
it easy to connect the braided steel air line. Once I had air going into
the tank, I threaded a compression fitting for the 5/16" air line into
the air tank and quickly discovered I would need to get some
90-degree connectors. The nylon air hose just doesn't have a very
tight bending radius. I needed 90-degree connectors for both the air
line to the horns, and the air intake line for the compressor. Without
the angled connectors, the air line tended to get in the way of the
drive shaft.
Routing the line along the inside of the frame rail is relatively easy.
Routing it from the frame to the engine bay, not as much. For
reasons explained later, I needed the air line to be accessible under
the hood. I routed the line along the inside of the drivers side wheel
well, which requires much care in securing the line. In routing the air
line through this area, it's remarkably easy to let the line rest against
hot engine parts on its way into the engine compartment. During my
initial weekend at the farm mounting the horns, tank and
compressor, I could smell something getting hot when I popped the
hood after driving home. Fortunately I figured out what happened
before testing the system, and even more fortunate was my earlier
purchase of an extra 20 feet of 5/16" nylon air line from
McMaster-Carr.
One thing I did differently than most was mount the pressure switch
inside the engine compartment. While the switch appears to be
relatively water resistant, I didn't want it attached directly to the tank
where it could potentially take a beating on the underside of the
vehicle. Plus, it would be one more small-gauge wire to take care in
protecting on its way from the engine bay to the tank. To accomplish
this, I needed to tee into the air line under the hood. The pressure
switch would be connected at the tee and monitor pressure from
that point, rather than directly at the tank. The pressure switch has a
1/8" male connection, so I found a tee at McMaster-Carr with a 1/8"
male connector and two 5/16" compression fittings. A dual-female
1/8" connector from home depot completed the hookup
With the air lines complete, I screwed in a drain cock and a 175 psi
pressure release into the spare ports on the air tank. The remaining
ports will serve as auxiliary air for whatever I can think of that might
be interesting.
Giving the system some electrical juice was the next task. The
compressor needs a direct line from the battery, by way of the
pressure switch (with its internal relay). The Hornblasters.com
instructions outline this pretty well. In between the battery and the
pressure switch is a 40 amp fuse. With the compressor being the
third component in my Blazer needing direct juice from the battery
(the main amp and subwoofer amp for the sound system were the
other two), I decided it was time for a fused distribution block from
Lightning Audio.
The pressure switch needs its owns power source to function, and
this power comes from the ignition wire of your choice. I chose the
power wire for the cruise control module. I also used this to power
the solenoid in the air valve. If wired this way (per the
Hornblasters.com instructions), the pressure switch will only be
functional when the ignition is on, which prevents accidental battery
drain. I went a step further and added a manual switch inside the
cab, just in case I didn't want the compressor running under any
circumstances. This switch is wired between the cruise control
module wire and the pressure switch lead. If the compressor switch
relay can't get any juice, it can't turn on the compressor.
I installed a push button for activation of the solenoid, mounted in
the console just under the headlight switch. The button went where
some optional switch of some sort would have been (fog lights,
maybe?). The wiring harness actually plugs into a plastic housing
on the back side of the console, even though there's nothing there
on the front side. I simply drilled out a hole big enough for the button,
screwed in the button, routed the wires through the dash and
firewall and put the console all back together again.
Again, I took this a step further. I tend to favor my left hand when
steering, so pushing a button with my left hand would require a
quick switch of hands on the steering wheel. The ideal location of a
button switch would be on the shifter, but I couldn't think of a good
way to mount it without calling attention to it. So I added a second
button switch that's more of a hand trigger, complete with a coiled
cord. While driving through the streets of Chicago, I can hold the
trigger switch in my right hand and steer with my left. The second
switch also lets passengers take part in the fun of blasting
unsuspecting drivers and pedestrians.
| It's good to have plenty of 90-degree angled connectors. That nylon line doesn't like to bend much. |
| Nylon vs. Heat |
| Four bolts to remove... |
| ...one hole to drill... |
| ...and it's all ready for the button. |
| Back side - button installed. |
| All ready to go back in the console. |
| The Magic Button |
| Pressure switch, 1/8" T-connector with 5/16" compression fittings, and the air compressor filter. |
| Filter |
| Pressure Switch |
| One more hole in the firewall.... |
FM antennae
Subwoofer amp
power wire
power wire
<--- Main amp
power wire
power wire
Horn button and
compressor cutoff
switch
compressor cutoff
switch
The Results
It's loud...what can I say. The first time I pushed the magic button, I
didn't just hear the horns, I felt them. And the first time I blasted an
annoying driver, well, let's just say the surprise and shock was worth
every penny. I was never so proud to be a redneck in the City of
Chicago.
Hear it!!
It's loud...what can I say. The first time I pushed the magic button, I
didn't just hear the horns, I felt them. And the first time I blasted an
annoying driver, well, let's just say the surprise and shock was worth
every penny. I was never so proud to be a redneck in the City of
Chicago.
Hear it!!
| Compressor shut-off switch |
| Lightning Audio fused distribution block. The King of Cheap strikes again: who needs fancy 4-gauge amp wire when you can buy a 4-gauge battery cable for $5 at Farm & Fleet? |
| Step 1 in rigging up a hand-held button switch: this is a panel mount DC jack from Philmore Mfg, available at Fry's. I spliced into the two wires on either side of the dash-mounted button switch, then soldiered one wire to the power lug and the other wire to the ground lug. |
| Next, I connected a DC power plug (also from Fry's) to a Pilot hand-held button switch from cardomain.com. I wasn't interested in the panel jack providing any power to anything - all I wanted was for the button switch to complete the circuit and fire the horns. It worked. |
| Beautiful...absolutely gorgeous. Now everyone can join the fun! |
| Here's a really funny video of train horns in action |
| Onboard Air! |
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