My speedometer fix
09-18-2011, 01:55 AM
#1
Registered User
Thread Starter
My speedometer fix
Since the swap of the NV5600 back in 2001, the speedometer and odometer in my '90 haven't worked.
It was about a year ago that I bought the following items from Dakota Digital.
Item Number | Description:
SEN-4165 | 4K Pulse Magnetic Pick-up coil for transmissions without a speed cable or VSS output.
SGI-5 | Universal Speedometer Signal Interface
Shortly after purchasing these 2 items, I mounted the pick-up coil that generates an AC current from the 4 magnets spaced 90degs. (12, 3, 6 and 9 o'clock positions) from each other on the driveshaft. Today, I finally got around to running the wires to connect to the SGI-5.
I soldered additional lengths of 12ga. wire to the pigtails on the pick-up coil in order to make the run all the way under the dash. Once inside the cab, all that was left to do was piggyback an ignition-hot circuit to power the SGI-5, find a good grounding point (a small, green LED will illuminate when it sees good a 12v signal and ground), insert the 2 wires from the pick-up coil into the SGI-5 cavities labeled "Input" and "Sensor Gnd," and utilize "Output 1" cavity for a signal wire to the speedometer. Since the SGI-5 receives an AC current from the pick-up coil, it won't matter which wire is the "input" or "ground."
Now, what to do with the signal wire from the "output" to the speedometer? Referring to the FSM, I found the wiring diagram for the plugs in the back of the instrument panel. The wire labeled "20WT/OR" (20ga wire, white with an orange tracer) in cavity 6 of the 6-way harness is the wire which feeds the tracer on the circuit board up to the speedometer. In the following picture, cavity 6 is on the right side. As you can also see, it carries the 20ga. white/orange tracer wire from the 2-way harness that would plug into the VSS in the transmission.
I bypassed the factory vehicle wiring in case of any possible shorts between the 2-way harness at the transmission and the 6-way harness at the back of the instrument panel. I pulled the white/orange tracer wire and terminal from the plug, piggybacked the signal wire from the SGI-5, then pushed and locked the terminal back into the plug.
Here's the SGI-5 after I locked all necessary wires into their cavities.
Among the instructions are multiple "applications" for the SGI-5. Each application allows the SGI-5 to calibrate signals in various ways. One way allows it to calibrate a signal for an OEM or aftermarket speedometer. In my case, Application #2 does just that.
I didn't get a chance to go for a drive since I finished about 9pm, long after the sun went down. The wires aren't tied up and the SGI-5 isn't mounted anywhere yet until tomorrow when I can drive the truck with a GPS and correct whatever reading I get.
For those who seem to have consistent problems with cruise control due to the VSS, wiring and whatnot, this could be a fix for you as well. Not to mention, correcting your speedometer for changes in tire size or gear ratios would be far easier with the SGI-5!
I hope this could be a benefit to some of you out there!
It was about a year ago that I bought the following items from Dakota Digital.
Item Number | Description:
SEN-4165 | 4K Pulse Magnetic Pick-up coil for transmissions without a speed cable or VSS output.
SGI-5 | Universal Speedometer Signal Interface
Shortly after purchasing these 2 items, I mounted the pick-up coil that generates an AC current from the 4 magnets spaced 90degs. (12, 3, 6 and 9 o'clock positions) from each other on the driveshaft. Today, I finally got around to running the wires to connect to the SGI-5.
I soldered additional lengths of 12ga. wire to the pigtails on the pick-up coil in order to make the run all the way under the dash. Once inside the cab, all that was left to do was piggyback an ignition-hot circuit to power the SGI-5, find a good grounding point (a small, green LED will illuminate when it sees good a 12v signal and ground), insert the 2 wires from the pick-up coil into the SGI-5 cavities labeled "Input" and "Sensor Gnd," and utilize "Output 1" cavity for a signal wire to the speedometer. Since the SGI-5 receives an AC current from the pick-up coil, it won't matter which wire is the "input" or "ground."
Now, what to do with the signal wire from the "output" to the speedometer? Referring to the FSM, I found the wiring diagram for the plugs in the back of the instrument panel. The wire labeled "20WT/OR" (20ga wire, white with an orange tracer) in cavity 6 of the 6-way harness is the wire which feeds the tracer on the circuit board up to the speedometer. In the following picture, cavity 6 is on the right side. As you can also see, it carries the 20ga. white/orange tracer wire from the 2-way harness that would plug into the VSS in the transmission.
I bypassed the factory vehicle wiring in case of any possible shorts between the 2-way harness at the transmission and the 6-way harness at the back of the instrument panel. I pulled the white/orange tracer wire and terminal from the plug, piggybacked the signal wire from the SGI-5, then pushed and locked the terminal back into the plug.
Here's the SGI-5 after I locked all necessary wires into their cavities.
Among the instructions are multiple "applications" for the SGI-5. Each application allows the SGI-5 to calibrate signals in various ways. One way allows it to calibrate a signal for an OEM or aftermarket speedometer. In my case, Application #2 does just that.
I didn't get a chance to go for a drive since I finished about 9pm, long after the sun went down. The wires aren't tied up and the SGI-5 isn't mounted anywhere yet until tomorrow when I can drive the truck with a GPS and correct whatever reading I get.
For those who seem to have consistent problems with cruise control due to the VSS, wiring and whatnot, this could be a fix for you as well. Not to mention, correcting your speedometer for changes in tire size or gear ratios would be far easier with the SGI-5!
I hope this could be a benefit to some of you out there!
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dsand (12-21-2016)
09-19-2011, 04:10 PM
#3
Registered User
Thread Starter
Success!
To begin with, I swapped out the original speedometer for a known working speedometer from a cluster I bought last year. I think the original finally took a dump some time ago because after mounting the pick-up coil, I would see it start dancing around when I was around 60-65mph yet, the odometer wasn't counting mileage and finally the speedometer quit altogether at some point.
At first, I wasn't seeing a reading at lower speeds. It wasn't until about 50mph that the speedometer jumped and moved around a bit. I called Dakota Digital's tech support for troubleshooting help.
I must say, their techs are very knowledgeable with their product! I got a thorough yet simple answer to every question I had. Not to mention, the techs I've spoken with have been easy to talk to and personable.
It was determined that the problem was more than likely the fact that the pick-up coil wasn't quite close enough to the magnets to read the low frequency it puts out at lower speeds. I moved the coil about 1/4" closer to the magnets and took it for a spin. I get a reading at about 15mph now and with only a couple pushes of the "DOWN" button on the SGI-5, the speedometer is dead accurate!
I was able to watch the odometer counting mileage as well. I'm stoked to have a working speedometer and odometer again. Even though, for as long as I've owned the truck and long before then, they hadn't worked. I always made mental notes of what gear the transmission was in and what RPM the engine was turning when passing by roadside radars to at least have an idea of how fast I'm going. It will take some getting used to watching it while I'm cruising down the road. I'm glad there was an aftermarket company, such as Dakota Digital, that had the means to fix something like this.
Like I said in my original post, this could be a great fix for others having issues with their speedometer.
To begin with, I swapped out the original speedometer for a known working speedometer from a cluster I bought last year. I think the original finally took a dump some time ago because after mounting the pick-up coil, I would see it start dancing around when I was around 60-65mph yet, the odometer wasn't counting mileage and finally the speedometer quit altogether at some point.
At first, I wasn't seeing a reading at lower speeds. It wasn't until about 50mph that the speedometer jumped and moved around a bit. I called Dakota Digital's tech support for troubleshooting help.
I must say, their techs are very knowledgeable with their product! I got a thorough yet simple answer to every question I had. Not to mention, the techs I've spoken with have been easy to talk to and personable.
It was determined that the problem was more than likely the fact that the pick-up coil wasn't quite close enough to the magnets to read the low frequency it puts out at lower speeds. I moved the coil about 1/4" closer to the magnets and took it for a spin. I get a reading at about 15mph now and with only a couple pushes of the "DOWN" button on the SGI-5, the speedometer is dead accurate!
I was able to watch the odometer counting mileage as well. I'm stoked to have a working speedometer and odometer again. Even though, for as long as I've owned the truck and long before then, they hadn't worked. I always made mental notes of what gear the transmission was in and what RPM the engine was turning when passing by roadside radars to at least have an idea of how fast I'm going. It will take some getting used to watching it while I'm cruising down the road. I'm glad there was an aftermarket company, such as Dakota Digital, that had the means to fix something like this.
Like I said in my original post, this could be a great fix for others having issues with their speedometer.
07-31-2012, 02:02 PM
#6
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I tried it.. worked like a champ! I have the Getrag 5sp in a 2wd ext cab.
The first time the magnets exited on the road. The zip tie mounting method sucks! Dakota sent me new magnets free of charge --> great customer service.
I mounted the sensor at the carrier bearing. There was a nice flat spot to mount the sensor to. I used a pair of dial calipers to scribe lines for the magnets. They end up at 2.106" apart. I then scribed a line about 1" from the end of the shaft and very lightly cleaned the shaft with a grinder. a dab of super glue under the magnets and epoxy over them has them set for good.
I put a ground wire to the a new screw in the column support behind the cluster, power from the blue/white on the round plug, output went to the white/orange listed above. I used output 4 with the switches 1,2,3 off 4 on.
Make sure you disconnect the oem VSS. it causes problems even when it's not working.
A short trip down the street and a tomtom calibrated it. get it in the ball park and set the cruise on a relatively flat road then adjust the calibration until the speedo and the gps match. Chasing it with your foot is tough. I drove away from the house two miles and plotted a course with the gps back. then followed the course. The Odometer was spot on. I have to drive a 165mi to Dallas tomorrow. I'll verify the odometer then as well.
FWIW,
Mark
The first time the magnets exited on the road. The zip tie mounting method sucks! Dakota sent me new magnets free of charge --> great customer service.
I mounted the sensor at the carrier bearing. There was a nice flat spot to mount the sensor to. I used a pair of dial calipers to scribe lines for the magnets. They end up at 2.106" apart. I then scribed a line about 1" from the end of the shaft and very lightly cleaned the shaft with a grinder. a dab of super glue under the magnets and epoxy over them has them set for good.
I put a ground wire to the a new screw in the column support behind the cluster, power from the blue/white on the round plug, output went to the white/orange listed above. I used output 4 with the switches 1,2,3 off 4 on.
Make sure you disconnect the oem VSS. it causes problems even when it's not working.
A short trip down the street and a tomtom calibrated it. get it in the ball park and set the cruise on a relatively flat road then adjust the calibration until the speedo and the gps match. Chasing it with your foot is tough. I drove away from the house two miles and plotted a course with the gps back. then followed the course. The Odometer was spot on. I have to drive a 165mi to Dallas tomorrow. I'll verify the odometer then as well.
FWIW,
Mark
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