Navigation System Dead Reckoning

[JJ Simba05 FLSTCI02]

Can anyone help with this, I purchased a Garmin Street Pilot 7500 which comes with a Dead Reckoning cable. The cable calls the two wires be connected as follows. One to the reverse light switch and one to the vehicle speed sensor signal.

Can anyone help me locate these two wires in my 2005 W22 chasis?

Thanks in advance for your help.

JJ

[JJ Simba05 FLSTCI02]

Can anyone help with this, I purchased a Garmin Street Pilot 7500 which comes with a Dead Reckoning cable. The cable calls the two wires be connected as follows. One to the reverse light switch and one to the vehicle speed sensor signal.

Can anyone help me locate these two wires in my 2005 W22 chasis?

Thanks in advance for your help.

JJ

[Redlands Truck and RV]

JJ,

Help me out here......isn't dead reckoning something used on the water for going straight between 2 points, as in no turning?

[oemtech]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> Dead reckoning (DR) is the process of estimating one's current position based upon a previously determined position, or fix, and advancing that position based upon known speed, elapsed time, and course. </div></BLOCKQUOTE>

Oh wow... haven't seen this since I was a radarman in the Navy... some 45 years ago. Yes, DR is probably used mostly in marine applications. But, it could apply on land as well. The only time you might use this is if and I say IF you lose your satellite reception for a long period of time. Otherwise the GPS should be able to pin point your location down to a few feet most of the time.

As to your original question... I do not know.

But if you have a backup camera that is tied to the reverse wire...

The Actia documentation has the following:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">5.1.2. Speedometer
Vehicle speed is read from a frequency input (pin 14) at the rate of 4000 pulses/mile. On board diagnostics can report the speedometer frequency input where 1.11 Hz = 1 MPH. If the frequency input to the cluster is missing, the cluster will display vehicle speed by reading it from the J1850 data bus. In this case, the needle movement can be jumpy due to the slow rate of transmission on the bus.
</div></BLOCKQUOTE>

[JJ Simba05 FLSTCI02]

OEMTECH

You are correct it is for when you lose sattelite reception, such as in going through tunnels, or in a city with tall buildings..

So does anyone know what wire is the speed sensor signal wire???

[John-D]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Redlands Truck and RV:
JJ,

Help me out here......isn't dead reckoning something used on the water for going straight between 2 points, as in no turning? </div></BLOCKQUOTE>

That is one use, another uses the vehicle motion sensors and a compass to do much the same thing on land, it can count factor in turns.

An example of dead reckoning on land.

walk forward 10 paces, now turn hard right (90 degrees) and walk 10 paces (Assume there is something blocking your path) now turn hard left (90 degrees) and walk 10 paces, now turn hard left again (90 degrees) and walk 10 paces, Now turn hard right (90 degrees) and walk forward 10 paces. You are now 30 paces directly foreward from where you started.

If you know the length of your pace, the original direction in which you were facing and where you started you can plot your location on a map.

This is basically what the Garmin does. While it has a clear view of the sky it takes a location, counts revolutions of your tires and takes a location, from these two figures it knows how far you travel per revolution. Now buy using a simple compass, most likely a flux gate (Which it can calibrate by various means including the above method) it can tell where you are, based on direciton of travel and number of revolutions, even when it has not got a clear view of the sky.

Very advanced, and very handy. Of course if you "HOT ROD" (Spin your tires) or slid on wet pavement when you hit the brakes or otherwise do not track true you will be off.. But soon as it sees sky again.. It will re-sync with the birds and there you are, right where the DOT appears on the map.

[Bob (WA0MQE)]

Jimmy... do you have the Service Manual (CD)? I found a reference to VEHICLE SPEED in the W22-L18.pdf file. This file includes schematics and diagrams for the chassis. On page 18, Sheet #020 and page 32, which is Sheet #081 there is are references to Powertrain Control Module Vehicle Speed.

Don't take my word for it, research it more for yourself, but this appears it could be what you are looking for. Personally I'd be absolutely sure what it will/or will not do before connecting any external equipment to any of these wires.

[John-D]

You know ... One option you might try (Worked for me) I wanted to add a repeater indicator to my rig, (Due to my size I can not see the HIGH BEAM) indicator on my rig, so I put a "Low Beam" indicator (as it turns out, snagged the wrong wire) where I could see it)

I E-Mailed Workhorse, they were very helpful