08 ram 1500 4.7L speed sensor

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"maxpower" <gjbeasley RemoveThis @comcast.net> wrote in message
news:_t6dncCFVcQtHgjVnZ2dnUVZWhednZ2d@comcast.com...
>
> "jp" <fangdoc RemoveThis @net-thing.net> wrote in message
> news:1217734685_6@pronews.com...
>> I have an 08 1500 quad cab, 4.7L, 6speed. I installed a Pioneer AVIC-N4
>> navigation system in it and have not been able to locate the speed sensor
>> wire to finish connecting my unit. Any help would be great!!!
>>
>> Thanks.
>>
>>
>>
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> I see a check engine lite coming on soon!!
>
> Glenn Beasley
> Chrysler Tech
>
>



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 >> Stay informed about: 08 ram 1500 4.7L speed sensor 

>I have an 08 1500 quad cab, 4.7L, 6speed. I installed a Pioneer AVIC-N4
>navigation system in it and have not been able to locate the speed sensor
>wire to finish connecting my unit. Any help would be great!!!

Okay... now that all the histrionics are over with, let's see if we can
actually offer some assistance.

The Pioneer unit simply wants a pulsed input from the rear wheel speed
sensor. While not absolutely required (as it can determine speed via GPS),
it does help the system respond more quickly to changes in vehicle speed.
Given that it's designed to go in to a multitude of vehicles, it will
automatically calibrate itself to determine the pulse-per-minute to vehicle
speed ratio (again, using the GPS readings).

So, in short, all you need to do is tap the rear wheel speed sensor wire
before it goes into the ABS controller. Unfortunately, the 2008 wiring
diagrams aren't yet available on Dodge's site
(http://www.dodge.com/bodybuilder), so you're going to have to wing it with
the wiring. Examine the connector at the rear differential, identify the
colors of the wires, and find them up at the ABS computer connector.
Assuming they didn't change anything from '06 to '08, you're looking for pin
#42, a 20-gauge dark green/white wire. That's the positive side of the
speed sensor, and probably what the Pioneer is looking for.
 >> Stay informed about: 08 ram 1500 4.7L speed sensor 

Good reason. There is no speed sensor. Vehicle speed is computed by a Hall
Effect sensor mounted in the rear differential. That , in turn, feeds the
ABS, and the chassis computer where the pulse train is measured against time
and then divided by a series of divisors for the various outputs like the
speedometer and display computer overhead. Normally, the GPS itself measures
speed (VMG) by calculating position change over time.
Steve

"jp" <fangdoc.TakeThisOut@net-thing.net> wrote in message
news:1217734685_6@pronews.com...
>I have an 08 1500 quad cab, 4.7L, 6speed. I installed a Pioneer AVIC-N4
>navigation system in it and have not been able to locate the speed sensor
>wire to finish connecting my unit. Any help would be great!!!
>
> Thanks.
>
>
> ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet
> News==----
> http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+
> Newsgroups
> ----= East and West-Coast Server Farms - Total Privacy via Encryption
> =----
 >> Stay informed about: 08 ram 1500 4.7L speed sensor 

No wonder. Thanks.

"Steve Lusardi" <stevenospam RemoveThis @lusardi.de> wrote in message
news:g73vk9$jge$00$1@news.t-online.com...
> Good reason. There is no speed sensor. Vehicle speed is computed by a Hall
> Effect sensor mounted in the rear differential. That , in turn, feeds the
> ABS, and the chassis computer where the pulse train is measured against
> time and then divided by a series of divisors for the various outputs like
> the speedometer and display computer overhead. Normally, the GPS itself
> measures speed (VMG) by calculating position change over time.
> Steve
>
> "jp" <fangdoc RemoveThis @net-thing.net> wrote in message
> news:1217734685_6@pronews.com...
>>I have an 08 1500 quad cab, 4.7L, 6speed. I installed a Pioneer AVIC-N4
>>navigation system in it and have not been able to locate the speed sensor
>>wire to finish connecting my unit. Any help would be great!!!
>>
>> Thanks.
>>
>>
>> ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet
>> News==----
>> http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+
>> Newsgroups
>> ----= East and West-Coast Server Farms - Total Privacy via Encryption
>> =----
>
>



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 >> Stay informed about: 08 ram 1500 4.7L speed sensor 

Tom,
I have never questioned you before, but this time I must question whether
this will work. If you tap into the sensor lead there, is it before or after
the pulse amplifier? If it is before, the signal level is very weak and
cannot drive anything but the input to the pulse amp. Perhaps I have
misunderstood your directions and you are refereing to the output of the
amp.
Steve

"Tom Lawrence" <tlawrence5 RemoveThis @earthlink.not> wrote in message
news:4895c3da$0$33678$892e0abb@auth.newsreader.octanews.com...
> >I have an 08 1500 quad cab, 4.7L, 6speed. I installed a Pioneer AVIC-N4
> >navigation system in it and have not been able to locate the speed sensor
> >wire to finish connecting my unit. Any help would be great!!!
>
> Okay... now that all the histrionics are over with, let's see if we can
> actually offer some assistance.
>
> The Pioneer unit simply wants a pulsed input from the rear wheel speed
> sensor. While not absolutely required (as it can determine speed via
> GPS), it does help the system respond more quickly to changes in vehicle
> speed. Given that it's designed to go in to a multitude of vehicles, it
> will automatically calibrate itself to determine the pulse-per-minute to
> vehicle speed ratio (again, using the GPS readings).
>
> So, in short, all you need to do is tap the rear wheel speed sensor wire
> before it goes into the ABS controller. Unfortunately, the 2008 wiring
> diagrams aren't yet available on Dodge's site
> (http://www.dodge.com/bodybuilder), so you're going to have to wing it
> with the wiring. Examine the connector at the rear differential, identify
> the colors of the wires, and find them up at the ABS computer connector.
> Assuming they didn't change anything from '06 to '08, you're looking for
> pin #42, a 20-gauge dark green/white wire. That's the positive side of
> the speed sensor, and probably what the Pioneer is looking for.
>
 >> Stay informed about: 08 ram 1500 4.7L speed sensor 

> I have never questioned you before, but this time I must question whether
> this will work. If you tap into the sensor lead there, is it before or
> after the pulse amplifier? If it is before, the signal level is very weak
> and cannot drive anything but the input to the pulse amp. Perhaps I have
> misunderstood your directions and you are refereing to the output of the
> amp.

Well, let me ask you this: if you hooked up a multi-meter to the sensor,
and set it to read A/C millivolts, do you think the meter would register
anything as the wheels turned? And if so, why do you think the electronics
in the nav unit would be any different?
 >> Stay informed about: 08 ram 1500 4.7L speed sensor 

Tom,
To your question, no, a 20k ohm per volt meter movment would most likely
kill the signal. Hall effect sensors are driven with a constant voltage that
build a magnetic field at the coil in the pick-up head. When the tooth wheel
enters the magnetic field, some of the field is absorbed by the wheel. This
increases the current draw at the source and it is this change of current
the amplifier detects. Even using a very high impedance oscilliscope probe
will attenuate the signal and be very hard to see on the display. In order
to use the speed pulse train, your signal tap will have to be after the amp.
Further complicating this, is the fact that the schematics and wiring
diagrams that I have seen do not identify what circuitry is on the wire
ends. Perhaps you know how to detect whether a particular pin on a connector
is a driver or a receiver, I don't, but if you know how to do that, I would
certainly like to know.
Steve

"Tom Lawrence" <tlawrence5 RemoveThis @earthlink.not> wrote in message
news:489766a2$0$33686$892e0abb@auth.newsreader.octanews.com...
>> I have never questioned you before, but this time I must question whether
>> this will work. If you tap into the sensor lead there, is it before or
>> after the pulse amplifier? If it is before, the signal level is very weak
>> and cannot drive anything but the input to the pulse amp. Perhaps I have
>> misunderstood your directions and you are refereing to the output of the
>> amp.
>
> Well, let me ask you this: if you hooked up a multi-meter to the sensor,
> and set it to read A/C millivolts, do you think the meter would register
> anything as the wheels turned? And if so, why do you think the
> electronics in the nav unit would be any different?
>
 >> Stay informed about: 08 ram 1500 4.7L speed sensor