QuestionQUESTION: I am stumped. I replaced the odometer gears today and the speedo needle still is not moving. The digits are moving ok. I followed the video on how to put the speedo unit back together(I had to remove the needle to get at the gears). I had my son check the solders. They seem ok. I previously replaced the vehicle speed sensor. Where should I check next? Is there a fuse just for the speedo? The contacts look clean. There is a bit of rust on the reset assembly for the odometer. I did not grease it yet. Should I use white lithium on that? All the other dials work fine in the cluster. However, when I turn the headlights on, the bulb for the right turn signal indicator faintly glows. Thought that was kind of strange. If you can refer me to any sites that have visual information, that would be most helpful. I tend to understand better if I can watch and repair at the same time. Thank you so much.
ANSWER: Hi Cheryl,
The distance sensor drives both the speedo and the odo. So if the odo is working the signal should be also 'seen' by the speedo. About the only possibility is that the power to the speedo is not there. (But then I believe the odo gears wouldn't move either). That is at the middle pin, so if you plug in the cluster and turn the key to 'run' check whether there is 12v reading between the middle pin and the lower pin of the speedo head. (The upper pin is the distance sensor signal wire).
Did the speedo work just before you changed the odo geara? If it did then something happened to it in the odo repair. If not, and before you started neither the speedo nor the odo worked, and now the odo works, then the speedo must have failed earlier along with the odo gearing.
However, one final possibility is that the speedo needle is on the wrong side of the pin at the 0 position of the dial. If so, then remove the needle and put it back on at the correct side.
Roland
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QUESTION: Neither speedo or odo worked when I bought the car. With the gear replacement, that remedied the odo problem.The old gears were cracked and missing teeth. The needle still does not move. What I found odd in the video is that they said to unscrew the needle to remove it but to press it back on and not screw it back on. I tried pressing it on and then screwing it back on and still nothing. I think I will take one of those voltage checkers that looks like a screw driver with a ground wire to see if there is any juice going to those three prongs behind the speedo head. That is ok to do, right? I tried to reposition the needle a few times, but that didn't work either. Not sure if I am doing that right. I got everything else to work on the car and this is the last thing that left to fix. Thanks
AnswerHi Cheryl,
You can verify that there is 12v between the middle pin and the lower pin of the speedo head. The upper pin is simply a pulsing low voltage pin generated by the distance sensor on the transmission so because the odo gears are moving that connection to the upper pin must be alright; and I suspect that you will find 12v between the middle and the lower pin because otherwise I believe the odo gears would not move. Check on the back side of the upper pin to verify that wherever that connects it is connected as the pulsing of the upper pin has to drive the speedo and the odo and I am not sure whether that is done by a single wire on that upper pin or by two separate wires on that pin (one to drive the needle/one to drive the odo)?
If you want to verify the speedo is not working (and that the issue has nothing to do with the needle per se), then you could jack up the right front wheel from the ground, start the engine with the parking brake on, then put it in drive and you should see the odo gears turning as the right wheel spins freely while off the ground. Then rev the engine a bit to simulate driving at 10 or so mph and observe for any signs of motion in the speedo/needle part of the unit. If none, then there is something definitely wrong with the speedo. I have no info on how to troubleshoot that part of the speedo head. You may just need to replace the speedo head as a unit (and save the good odo gears in case needed) getting it from a wrecking yard.
Roland
