91 SC1

[JJ]

I have a 91 SC that has suddenly had the odometer stop working. All the other gages, tach, and speedometer work just fine. I disassembled the unit and cleaned and lubricated the odometer unit but it did not fix the problem. It seemed that the odometer must be bad so I bought a used complete head cluster at the local used parts store. The Odometer in that unit does not work either. Now, on to the question... Does anyone know why just the odometer would stop working and what can be done to repair it? Is there a sensor somewhere that regulates the odometer?

Thanks

 

[Dan Hicks]

I have a 91 SC that has suddenly had the odometer stop working. All the other gages, tach, and speedometer work just fine. I disassembled the unit and cleaned and lubricated the odometer unit but it did not fix the problem. It seemed that the odometer must be bad so I bought a used complete head cluster at the local used parts store. The Odometer in that unit does not work either. Now, on to the question... Does anyone know why just the odometer would stop working and what can be done to repair it? Is there a sensor somewhere that regulates the odometer?

So the speedometer working? I believe that unit is purely mechanical, so if the speedometer is working, the odometer should too. Could be the used unit was already broken.

Certainly when you disassembled the unit you should have seen the mechanism that connects speedometer to odometer, and anything that could interfere with the connection.

 

[John Jennings]

Thanks for the reply. The entire unit is hooked up electronically. There are no connections to the head cluster unit except wires. I traced the circuit board to make sure there were no burn looking marks. I guess the used unit was working since it had 144,000 miles on it. Everything works in both the old unit and the other one I put in except the odometer. Could it be there is some connection to the engine or wheels (?) that has a sensor that could be the problem? Ideas on a source to lookup the wiring? Thanks.

 

[Dan Hicks]

That still seems a little odd, as one would think that the speedometer and odometer would be run off the same pickup on the driveshaft. I wonder if there is some sort of interlock to allow the unit to be used as a demo without registering miles, or some such?

I suppose you might poke around on the transmission to see if there appear to be two separate speed pickups. Dunno where these would be, exactly, though.

 

[Robert Hancock]

There will only be one speed sensor. The only reason I can imagine for the odometer not working but the speedometer working, assuming a good replacement instrument cluster (which may not be a valid assumption here), would be some kind of strange power supply problem..

 

[John Jennings]

thanks, I was wondering that, too. Still, finding the diagram that would show which wire controls the odometer is my next problem. I have spent several hours looking on the net for one but have not had any luck yet. Any ideas are greatly appreciated. I don't think I want to go to the Saturn dealer to order a manual for the wiring diagram.