2007 Toyota Tundra Double Cab 5.7L V8 Limited
Pyrite Mica, Standard Bed, 20" Alloy Wheels
Owner: WileETundra
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Installation Report: NAV Speed Pulse Generator (enables
all functions while in motion)
Project Description
The factory navigation system in my 2007 Tundra is great but like many other NAV
units it has an irritating and
poorly-designed safety feature which disables many of the functions and on-screen
buttons whenever the vehicle is in motion. This is done presumably to
prevent the driver from being distracted while driving, however it doesn't take
into account that the front seat passengers will want to use those functions
(especially on long trips). This is a common problem on many vehicle NAV
systems and there are literally dozens of threads and thousands of posts on
forums all over the web with vehicle owners seeking a solution to enable all the
NAV functions while in motion.
For some NAV models you can purchase or burn a modified
firmware DVD which will enable the functions, however this can be expensive, the
burning process is tricky and requires a specific hardware / software setup, the
modified firmware often has to be initialized every time you start the vehicle, and
you will lose the bypass if you upgrade to the new factory firmware when it is released. The
ideal solution was to find some type of hardware
modification which will work with most NAV units and won't be tied to a specific
firmware version. Obviously I wanted something cheap, fairly easy to
acquire, easy to install, automatic to use, and reliable. I came up with the perfect solution after
hundreds of hours of research, firmware evaluations, vehicle wiring tests, and
some basic electronics tinkering.
The solution is a speed pulse generator device which fools the NAV unit into
thinking that your vehicle is not in motion even when you are driving at full speed.
This device should work with many vehicles and NAV units but I have only tested
it on my 2007 Tundra so make sure that your NAV unit uses a similar speed sensor
signal before trying this.
NOTE: You can buy one of these devices for
your vehicle instead of going through all the hassle of making your own.
See the Comments section below for details on how to order.
Photos
(click on any photo to see a larger version)
All the parts ready to go,
minus the wire and toggle switch:
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Schematic wiring diagram,
download and print as full-page:
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Front of the assembled circuit board:
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Back of the assembled circuit board:
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Use this exact layout for easy assembly:
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Clean solder joints with minimum jumpers:
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Small hole in the end for the wires:
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Side rails cut down slightly to fit the board:
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Mounting the circuit in the box:
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Screw the lid on and ready to install:
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Dash with the NAV removed:
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Speed sensor wire behind the NAV:
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Toggle switch and device in center console,
other switches
are for my other NAV mods:
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NAV unit showing pulse signal with no motion:
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Parts & Cost
Note: These are common parts available at any local Radio Shack
store or you can order them on the web.
- One 3"x2"x1" black plastic project box enclosure, Radio Shack part #
270-1801, $2.29.
- One small blank dual circuit board, Radio Shack part # 276-0148, $1.99.
- One 555 timer low power IC chip, Radio Shack part # 276-1718, $1.69.
You can substitute part # 276-1723 if needed.
- One 8-pin low-profile IC socket, Radio Shack part # 276-1995, $0.69.
- One 1K ohm 1/2 watt resistor, Radio Shack part # 271-1118, $0.99.
You can substitute part # 271-1321 if needed.
- One 33K ohm 1/2 watt resistor, Radio Shack part # 271-1129, $0.99.
- One 100K ohm micro potentiometer, Radio Shack part # 271-0284, $1.29.
- Two 22 micro-farad 35 volt DC electrolytic capacitors, Radio Shack part
# 272-1026, $1.19 each. You can substitute part # 272-1014 if needed.
- One SPDT two-position toggle switch.
This is for installation only and is not part of the speed pulse generator
itself. Radio Shack and many automotive stores sell lots of different
versions of these switches so buy whatever size and type of switch looks
good to you. I recommend something like Radio Shack part # 275-625 or part #
275-635 to keep it simple.
- About 6" of shielded 22 awg stranded copper conductor wire in
three different colors (black, red, and green), Radio Shack part # 278-1224,
$5.99. You can also slice open an old CAT5 or RJ-45 cable and remove
the individual wire conductors, or use any similar wire that you might have
around the shop.
- About 6' of two-conductor 18-24 awg stranded wire. Any speaker
wire or lamp cord will do but you can also buy some at Radio Shack if
needed, part #278-1509, $3.99 for a 75' spool.
- Approximately 2" of black heat-shrink tubing large enough to fit around
all three wires.
Tools
(just the major items, not a complete list)
- Soldering iron with a fine point tip
- Thin gauge 60/40 solder
- Tip-tinner /
cleaner
- De-soldering braid
- Nippy cutters
- Wire stripper
- Exacto knife
- Drill with bits
- Socket wrench and sockets
Assembly Process
NOTE: You can buy one of these devices for your
vehicle instead of going through all the hassle of making your own. If you
buy a device then you can skip this section and go straight to the installation.
See the Comments section below for details on how to order.
- Remove all electronic components from the packaging and lay them out on
a clear table. Prepare your tools and soldering gear as well.
The area should be brightly lit and you may need a magnifying glass if your
vision is not perfect for macro work.
- Use the nippy cutters to cut the dual circuit board in half on the
prefabricated line. You only have to start the cut on one edge and the
board will snap apart clean. Save the extra half for another project.
- Mount each component on the circuit board exactly as shown in the pictures
above. Do not install the 555 timer IC in the socket yet. Use the grid lines and markers on the circuit board to keep
everything properly aligned. You don't want to crowd the components
together unnecessarily or the soldering and wiring will be more difficult.
I believe the design above uses the fewest jumpers and is easier to
construct but you could actually lay your circuit board out however you want
as long as you connect the components properly per the wiring diagram.
- Flip the circuit board over and carefully solder each of the component
pins to the board. I find it helpful to use a small piece of scotch
tape or electric tape to hold the components in place when handling the
board. Do not use excessive heat or keep the iron on the
board too long or you can melt the board and damage the components.
Use only a tiny drop of solder on each pin and clean the iron in-between
each component so that it leaves the joints clean. It might be easier
for you to mount and solder one component at a time.
- Where jumper wires are needed you can simply bend over the extra long
leads from the components, run the leads to the next solder point, and trim
off any excess. Save the cut-off portions and use them for the really
small jumpers. Note that some pins have more than
one component or jumper connected to them. Avoid running jumpers on top of
other pins or jumpers which they do not connect with, however if this can't
be avoided then cut a small piece of shielded wire to use for the jumper and
make sure the shielding doesn't melt away during soldering. Do not bend the jumper wires more than necessary as
the thin solid wire can break easily. It is usually easiest to bend
the jumper in advance and lay it on the circuit board to make sure it fits,
then hold it in place with tweezers while soldering.
- Cut three pieces of wire about 6" long, one in each color. Strip
about 1/4" of the shielding from each end and solder one end of each wire to
the circuit board as shown in the wiring diagram. Use the black wire
for ground, red for +12 volts DC ignition, and green for the speed pulse output.
- Apply a short length of heat-shrink tubing over all three power wires close to
the circuit board edge but leave about 1/4" gap so the wires can be flexed
slightly without stressing the solder points.
- Carefully inspect each pin and solder joint to make sure they do not
touch or overlap with other pins, especially for the pins on the IC socket since they are tightly spaced and the solder can easily melt and short
two pins together. If you find an error then use the de-soldering
braid to remove the solder and try again.
- Set the 100K ohm micro potentiometer to the maximum
resistance point. This is easily done by inserting a small
screwdriver into the middle of the dial and turning it clockwise until it
stops. If you connected the potentiometer differently than shown in
the picture above then you might need to
turn the dial counter-clockwise to achieve maximum resistance. Do not
use excessive pressure.
- Carefully align the 555 timer IC pins with the socket and push it down
until it mounts flush against the socket. The IC has a small round dot
on it which marks pin number 1, you can see it in the top left corner in the
photo above. It is usually best to insert one row of the pins first
then push the other row of the pins inward gently with your fingernail
while inserting the other side.
- Test the circuit by connecting a 9-volt battery to the black (-) and red
(+) power wires. Then connect an analog voltage meter to the black
power wire (-) and green speed pulse output (+). If the circuit is working
properly then the needle on the voltage meter should briefly spike up
to about 5 volts when it is first powered up, then immediately drop back down
to rest between 0-1 volts. Every 1-2 seconds the needle will drop
rapidly backwards towards 0 for a fraction of a second and then return to
the resting position - this is the pulse signal. The rate of the pulse
varies based on the potentiometer setting but is generally close to 1 pulse
per second and it can be increased by reducing the potentiometer. If
your circuit is not working or the readings are different than stated here
then you most likely did not connect the components properly or you might
have one or more solder joints touching when they shouldn't. Also pay
special attention to the capacitors since they are polarized and must be
installed in the right direction.
- Open the project box and drill a small hole about 3/16" or just large
enough for the three wires and heat-shrink tube to fit through snugly.
Use the nippy cutters to trim about 1/8" off the top of each of the four
circuit board support rails on the inside walls.
- Mount the circuit board inside the project box with the components
facing down into the box, run the power wires out through the hole, and
attach the lid with the provided screws.
Installation Process
The following instructions are complete but if you want more detail on the
NAV wiring then I
recommend that you check out my other NAV report for more photos and detail on
my other NAV modifications. If you plan to do any of the other NAV
modifications then it is best to do all the wiring at one time so you won't have
to remove your NAV unit again later.
- Remove the factory NAV unit from the dash. This is surprisingly
easy and should only take about 15 minutes. The Metra product website
has instruction manuals which show how to remove your NAV unit.
Click here for the 2007 Tundra or
click here for other vehicles. For other vehicles you will need to go to
the Products page, click on "Select a Vehicle", specify your vehicle, click
Submit, select Kits from the drop down list, and then click on the kit.
The kit product page will have a link to download the instruction manual for
your vehicle.
- Locate the plug behind the NAV unit which contains the speed sensor
wire. On the 2007 Tundra DC Limited this is the small gray plastic K6
connector which has a total of 5 pins but only 2 wires running into it, and
the white wire on pin number 3 is the speed
sensor wire (see photo above). This might be a different connector or wire color for
your vehicle so check your vehicle wiring diagram to be sure.
- Cut the speed sensor wire and use wire nuts or solder to attach a 6'
extension onto each of the cut wires.
18-22 awg stranded wire is the best but you can use speaker wire or lamp
cord if needed.
- Run the extension wires to a convenient location for the speed pulse generator
and toggle switch. My device and switch are located inside the center
console along with a bunch of other switches for my other NAV mods but you can put yours almost anywhere including
the inside of the dash or glove compartment.
- Connect the wires as follows:
Red wire from the speed pulse generator circuit: any +12 volt source
that is switched on with the ignition
Black wire from the speed pulse generator circuit: vehicle ground
Switch Common: speed sensor wire that goes into the NAV unit
Switch ON # 1:
speed sensor wire that goes into the dash (to the vehicle ECU)
Switch ON
# 2: green speed pulse output wire from the speed pulse generator
- Mount the toggle switch and the speed pulse generator as desired.
Ideally they should be out of the way but removable if maintenance is needed.
On the 2007 Tundra I suggest placing them inside the center console, underneath the removable portion of the center console, above or
behind the glove box, or under the cigarette lighter assembly.
- Fire up the vehicle and test it out. If you are using firmware
version 6.1 then you can monitor the speed pulses by accessing the diagnostic menu:
turn on the vehicle, let the NAV unit boot up, hold down the INFO button for
several seconds and keep holding it, then turn your parking lights
on-off-on-off-on-off. Release the INFO button, go to the main
diagnostic menu, and select the Navigation Menu... Vehicle Sensors
option. Verify that the speed pulse count is continuously increasing but the
speed remains at 0-1mph.
Or you can just drive around and try the NAV functions while in
motion. When the toggle switch is in the ON # 1 position the NAV will function just like it did
from the factory and the features will be disabled when you are going more
than 5mph. When you flip the switch to the ON # 2 position then the
speed pulse generator kicks in and the NAV functions should be enabled all
the time.
Total Time: ~6 hours including prep and cleanup
Comments
- Works great: This is exactly what everyone wants - full NAV
functionality all the time whether you are in motion or not, and you even
have the option to switch back to factory mode at any time. This is
how the vehicle should have been shipped from the factory to begin with.
It should be compatible with all future firmware versions unless the NAV
programmers come up with some new way to disable the functions such as
relying solely on the GPS input, although this would have other
disadvantages and isn't likely. Time will tell but I think this
solution is bullet-proof unless / until the NAV units are redesigned for
future vehicles.
- Value: Overall this mod is a great value since the total
cost is only $15 and the functional improvement is amazing. Compare
this to spending $200 or more on modified firmware from CoastalTech, or to
the cost of burning several DVD coasters while trying to make your own
modified firmware and you come out far ahead with this device.
- Side effect: One minor issue is that the NAV unit normally
uses the speed sensor signal to enhance the GPS accuracy. When you
disconnect or alter the speed sensor signal the NAV unit has to rely solely
on the GPS data thus it is slightly less accurate when plotting your exact
position while you are in motion. In all of my tests the GPS reading was still
accurate but the maps wouldn't scroll as smoothly
between updates when I was driving. The position indicator would stay locked on a
specific location for a few seconds and then it would jump to the next spot.
Usually it would update my position once every 2-3 seconds or every 100' of driving
distance. This is not a big deal but it is worth mentioning. If
you want the smooth map scrolling then you can just leave the toggle switch in the factory position
until you need to enable the functions then switch it back to factory mode when you are
done.
- Not for the timid: If you haven't worked with electronic
components, circuit boards, soldering, and vehicle wiring before then this
may not be the best project for you to start out with. Soldering is an
art, especially when you are working with tiny components that can be ruined
by excessive heat, and it can be maddening to get all the pins and jumpers
soldered perfectly without shorting nearby pins. It only takes one bad
connection for the device to fail or work improperly. If the device
was wired improperly or becomes defective later then it could possibly
damage your vehicle wiring system, NAV unit, or ECU, or possibly even start
an electrical fire. If you aren't comfortable and experienced with
this type or project then don't try it, or consider hiring someone else to
do the work for you.
- Fried chips: If your device tested ok during assembly but
then it didn't work after installation then you most likely wired it up
wrong or you fried the IC chip. The timer IC is the most sensitive
part on the circuit board and it can be damaged by static, improper voltage,
or shorting the wires even if just for a split second. Try removing
the IC chip from the socket and replacing it with a new one. If this
doesn't work then you might have fried the other components so you will have
to test each one with a meter or start over and build a new device from
scratch, or just buy a completed unit as noted below.
- Special disclaimer: Of course you should still be cautious
and avoid using the NAV unit while driving. I made this device
primarily to allow my passenger to use the NAV functions while we are on
long trips but even that could be dangerous under some circumstances.
I also didn't test this device on other vehicles but it should work on many
NAV units according to my research. If you decide to build or use
this device then you do so at your own risk.
- Dude! Can you make one for me? Please, please, please...
I originally did not want to offer this service since my spare time is
limited and usually spent on other mods and projects for my own vehicle.
Many people have asked about it, though, and a lot of them do not have the
soldering skills to make their own circuit so I decided to help a few of
them out. So if you can't make your own device and you are willing to
pay $50 then I will make one for you. This price
includes $15 for the parts, $5 for US Priority Mail Shipping, and $30 for
several hours of my time to collect payment, shop for the parts, build the
device,
test it, pack it, and ship it. I generally ship these out on the very
next day after receiving your payment. If I
am too busy or I run out of parts then I will stop accepting orders. I
don't plan to build these for long so if you want one then you should order
now while you still can. If you
are interested then
click here to send a PM to me through the forum and I will reply with
payment instructions.
