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speedometer wiring diagram


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jacoby
New User

Jun 17, 2009, 2:48 PM

Post #1 of 5 (10639 views)
speedometer wiring diagram Sign In

My father has a 1999 Chevy s-10, that he converted to an electric vehicle. When we pulled the motor we eliminated a few too many wires, so now the speedometer doesn't work. I got the wires from the transmission for the back up lights to work, but not the speedometer. Can anyone help me with a wiring diagram for the speedometer?
mark.


DanD
Veteran / Moderator
DanD profile image

Jun 17, 2009, 10:42 PM

Post #2 of 5 (10627 views)
Re: speedometer wiring diagram Sign In

The vehicle speed sensor (VSS) on this year of S10; is a permanent magnet generator that produces an analog signal. This analog signal is sent to the powertrain control module (PCM) and is converted into a digital signal. This digital signal is then sent to the instrument cluster module and the radio. Why the radio; it get louder as you increase speed.
So without the PCM being used to do this conversion; you may need too somehow replace the VSS and wire it directly to the digital input of the cluster. A hall-effect sensor is another type of sensor that uses rotation to produce a signal and the hall-effect produces a digital signal.
How you would convert or retrofit a hall-effect to fit and work on the transmission; I’m not sure?
Maybe if you were to go up a few years in models that used the same transmission; they (GM) may have changed the sensor to a hall-effect?
Or go back a few years; when GM use to use a stand alone speed buffer module; it use to convert analog to digital.
Analog signal is a wave form type of signal; digital is a series of on and off signals or pulses of on and off. These on and off signals is what is known as binary (sp?) communications; that look if written out on paper as 0’s and 1’s; 0 being off 1 being on. The internals of the speedo (instrument cluster) is a computer on its own; computers only understand binary language.
Whichever way; you’ll need a signal of 4000 pulses per mile; so that the speedo will read accurately. That’s of course if you haven’t changed tire size or differential gearing.

Dan.

Canadian "EH"






(This post was edited by DanD on Jun 17, 2009, 11:05 PM)


jacoby
New User

Jun 18, 2009, 12:19 AM

Post #3 of 5 (10616 views)
Re: speedometer wiring diagram Sign In

The PCM is still there, and I think I have the two wires wired back into it. ( I had pulled quite a few of the wires that ran to the sensors on the engine out of the pcm. I thought maybe a wiring diagram would confirm what I have or what I am missing.


DanD
Veteran / Moderator
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Jun 18, 2009, 3:00 AM

Post #4 of 5 (10607 views)
Re: speedometer wiring diagram Sign In

I’m going to suggest going to GM, All-data or Mitchell's web site and buying some time in their manuals; print off the diagrams that you believe you’ll need.
There’s just too many to know exactly which ones you’ll want; for me to try and supply them.
For example there’s 2 diagrams for the cluster, 3 for a 2.2lt PMC and 4 for a 4.3lt engine. Today’s electronic wiring diagrams are not displayed all on one sheet.
The Instrument cluster diagram set of 2 diagrams; one shows the cluster and the other shows only portions of the PCM’s terminals/connectors that deal with the cluster.
Why you may need the PCM diagrams is to make sure that all of the power feeds and grounds are still intact.
You may have the wiring connected between the VSS, PCM and the cluster; but if the PCM is half brain dead from a missing power or ground, the speedo still isn’t going to work.
Dan.

Canadian "EH"






jacoby
New User

Jun 18, 2009, 4:55 AM

Post #5 of 5 (10599 views)
Re: speedometer wiring diagram Sign In

It probably is a ground like you suggest.... because when touching a test light to the pcm its lighting up, it probably should be grounded somehow.
thanks dan






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