Speedometer / Odometer Not Working. Read entire post.

Rtfm

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Also, from what little I could find on the 94-98 speedometers, the chip in question seems to have some programming with it. Being a Signetics chip, I was wondering about that. Seems I am probably correct. If I can get the chips in hand, they wouldn’t have the proper programming if they weren’t surplus NOS that Ford used. There were a few different speedometers in our narrow year range just in the year, engine, and max velocity, so finding even a NOS with the correct parameters is almost zero. I went ahead and just bought a same year/ model used cluster for mine today so I can get back on the road.
 

Connie

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I hope I'm not missing something in this thread. But, does the Speedo Needle in the Gauge Cluster try to move, or bounce at all? If it does, it may not be an Electrical Issue. A Speedo Gear can look good on the outside, but the HOLE the Cable goes into, may have stripped the inside part of the Gear itself. BOB.
 

Rtfm

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The speedometer in 94 and up has no gear. It is electronic. The previously posted pictures are the speedometer module.
 

Connie

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I should've known. Wasn't sure exactly what year the change took place. I'm sorry about that.
 
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Ryan Lawson

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Ryan, check the cruise control function to see if the signal gets to the ECM. The signal from the speed sensor goes straight to pins 11 and 12. See if you can get a low resistance (less than 1 ohm) path against a ground from pin 11. Check with an AC voltmeter across pins 11 and 12 when the car is in motion to check for a signal voltage. It should read over 1.5 volts or better with a forward speed of 10 mph or more. If you have no signal between those pins, check pin 12 and a good known ground for the AC signal from the speed sensor. If no voltage, then remove the sensor from the transmission and spin it up using a drill and you should get 6-9 volts out of it easily. If no voltage that way, the sensor is bad.
I can walk you through testing the speedometer on the bench, too. If you have signal across pins 11 and 12, then your speedometer should work if you are getting power from fuse 8 to the switched power (pin 16) and constant power through pin 13.

Ok, i'll try and check it out. I've been working a good bit of overtime and I haven't had much time to mess with it.


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Ryan Lawson

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Update: My speedometer is fixed. I checked all wiring and found no issues. I was having my car tuned at a local shop so I asked them to check behind me on the speedometer. They discovered that it was the circuit board like I suspected. They put one from a old speedometer in and fixed it. Thank you for all the help.


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Rtfm

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Same here, Ryan. Got mine back on the road tonight. I had to use a scavenged speedometer board from a donor ‘95 cluster. I changed out the bad 10 uF polar capacitor that was also failing in my old one, as well. It seems most of these old electrolytic caps are going bad in these 25 year old vehicles. The bipolar caps were good on my old one and the replacement. Hoping to get a few more years out of this one. At least I have replacements for the other instruments now.
 

Don Stewart

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Ok, so my speedometer and odometer are not working. All other gauges work correctly. I'm sure this question has been asked several times, but I cannot find a solution to my problem. Here's what I've done so far.

1. Changed out the worm & drive gear inside instrument cluster. No change.
2. Removed VSS and looked inside. Gears look fine.
3. Hooked VSS up to volt meter and spun with drill. It pulled 9 volts at a fast speed.
4. Pulled speedometer part of cluster from junkyard. Replaced the tiny motor the worm gear installs onto. No change.
5. Purchased new harness that plugs into VSS. No change.
6. Saw on google that the 15A fuse that runs the dome light may affect the speedo (not sure if that's true). Checked it anyway and it's fine.
7. Pulled passenger kick panel where the ECU is and located the pink/orange wire and gray/black wire that go to the VSS. Just wiggled them, kind of scared to mess too much in there. No change.

After all that, the only thing I can think of is the small control board for the speedometer inside the cluster may be bad. I have one from the junkyard but I really don't want to change that because the needle has to come off. On my last mustang I changed the overlays and the needles never were right again.

So, my questions are:
1. (obviously) Am I missing anything?
2. Can someone give me more detail on where the wires run from VSS to kick panel? I saw a post on ford460 forum where someone replaced the wires completely, but the guy was extremely vague.
3. Should I go ahead and replace the VSS just to see?
4. If I have to replace the control board, can someone give me detailed instructions on how to do it without screwing my needle movement?

My car is a 1994 cobra. 302 bored .030 over with DSS forged pistons. Trick Flow kit w/ cam. BBK shorty headers & cold air intake. 3.73 rear end gears.

Sorry for the long post, and thanks for any help.
I have a similar problem on a '94 GT. Does anyone know how to test the odometer motor for functioning properly? Also, is the odometer drive motor the same part for all models and engine combinations ('94-'98)? Maybe I could find a non-GT cluster locally to pull and remove the drive motor from.
 
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