Speedo And odo Are not working.

[dtbranden2]

I bought a 1997 Cobra. I was driving the car home and the speedo and odo quit working. I was doing some reading on these forums and they said it's generally the speed sensor on the tranny so i got under the car and the speed sensor looks brand spanking new. Where should i start to look or could someone point me to a link. I don't want to tear apart the dash unless i have to. Would it be in the cluster. All the other gauges work Besides speedo and odo.

 

[1989Gt.]

I bought a 1997 Cobra. I was driving the car home and the speedo and odo quit working. I was doing some reading on these forums and they said it's generally the speed sensor on the tranny so i got under the car and the speed sensor looks brand spanking new. Where should i start to look or could someone point me to a link. I don't want to tear apart the dash unless i have to. Would it be in the cluster. All the other gauges work Besides speedo and odo.

You pulled out the speedo gear from the trans and it looks new? If you havent pulled it pull it all the way out. Did you buy it without it working?

Or right when you took it home

 

[svtcobralover]

check the sensor on the passenger side of the engine bay. Its right behind the shock tower. Its a small tube looking like sensor and make sure its plugged and if it has a seperate ground attached to it, check that too. But my money would be the speed sensor.

 

[dtbranden2]

I will check the sensor in the engine bay when i get home from work. And as to your post i was pulling in the drive way and the speedo just dropped and didn't move, and no i haven't pulled it all the way out i am changing the tranny fluid tommorow i will pull it out and let you know. Ty for getting back to me so quick.

 

[mwolson]

I have no idea of what sensor svtcobralover is talking about. Maybe he can explain what he's talking about.

The VSS signal runs from the VSS sensor to the PCM and to the cluster. It runs very close to the exhaust pipes, so check that they haven't been melted first.

If the wires look good, re-seat the connector, and see if the speedometer starts working again.

If that doesn't get it to start working, unplug and pull out the VSS sensor. Put the VSS gear in the chuck of a drill and hook up an AC voltmeter to the pins. Spin the vss gear with the drill and look for an AC voltage on the pins. If you see an AC voltage, then your VSS is working, and your problem is in the wiring or the instrument cluster. Put the VSS back into the car and hook it back up.

In order to check if it's the cluster, get someone with a scantool (or an Xcal) to read the VSS signal in your PCM as you drive. If the PCM is seeing the speed signal, then you know the wiring to the PCM is good. You will have narrowed it down to the wire to the cluster and the cluster itself.

Once you get that much testing done, report back.

 

[dtbranden2]

I removed and replaced the VSS probelm still exsists.
I put it on my OBD II The PCM is getting signal for speed of the car.
So that elimates it to the cluster itself or the cluster harness.

Would you reccommend on pulling the front portion of the cluster and see if the harness came unplugged from the back of the cluster?
Or where should i proceed now?

 

[mwolson]

if you can spin the VSS, remove your cluster and look for an AC voltage with the VSS spinning across the VSS pin on the cluster connector and ground. You can get the pin number and wire color from my cluster pinout page: 94 to 98 Cluster Pinouts

If you are getting AC to that pin, then it sounds to me like your speedo has taken a crap. The speedometer circuit drives the stepper motor that drives the odometer, BTW, so if the speedometer has died, that is likely the cause of the odometer not working.

I have a bench setup for testing and calibrating clusters if you want to have me take a look at it for you.

 

[PSUCOBRA96]

sometimes the gears in the back of the speedo will wear out, not sure if they will cause a double failure like you are seeing but it is something you should be eliminating be examining the gears themselves.

 

[mwolson]

The gears only afffect the odometer, not the speedometer, but they do fail quite often.

 

[03bluemach]

My speedo stopped also .. I changed the odometer gears they were wore out and once i put everything back in the car the speedo quite working, i changed the gear on the vss as it was stripped when i took it out, went ahead and changed the vss to at that point.. Still no luck ,when i would drive the car an stand on it 1st-3rd the needle would start to move a lil .. Im thinking maybe i didnt put the speedo needle back on right ( to much or not far enough ) any thoughts on this Wolson ??? Thanks

 

[mwolson]

The VSS signal isn't being generated, it isn't getting to the cluster or the cluster is broken.

I assume you have re-seated all of the connectors to ensure you are getting good electrical contacts.

One possible issue is that the drive gear in the transmission tailshaft is worn out too. I am not sure if the drive grar is metal or plastic. I'd think it is metal, but maybe someone who has actually seen one knows for sure.

If you've pulled the speedometer needle off, then the only way to be sure to get it back on the shaft the right way is to drive the cluster with a calibration signal. That is also a good way to test the cluster too.

PM me if you are interested in me bench testing the cluster for you or if you are intersted in buying some cluster testing and calibration tools.

 

[mwolson]

I just added a how to that tells you how to test your speedometer (and tachometer) here: http://www.svtperformance.com/forums/how-278/809186-test-your-tach-speedometer.html#post11202552

 

[Boss 327]

I have this problem with my cobra also. My speedometer only works when I depress the clutch. Its driving me crazy

 

[mwolson]

I have this problem with my cobra also. My speedometer only works when I depress the clutch. Its driving me crazy

Is the cable rubbing on the clutch lever?

 

[03bluemach]

Thanks for the feed back .. i have to cluster out of the car right now and i pushed the needle on a lil bit more hoping this will fix the issue ( prob not lol ) once i get the car back up i will test it an go from there .. if all eles falls i will gladly send it your way !!

 

[Boss 327]

Is the cable rubbing on the clutch lever?

Not that i could see. I'll be looking more at it this week.