speedometer stopped working whats up? on 1995 Volvo 940

not sure just bought car few days ago. was working for about 6 miles. stopped! then after sitting for 8 hours and no rain, worked again about same amount of time.

Asked by for the 1995 Volvo 940
Hey Pat (and ninjamom), if I remember correctly, the VSS is on the rear differential on this vehicle. They didn't fail very often, in fact I'm trying to remember having to replace one for this problem and I can't.
What I do remember seeing were the instrument panel circuit boards and speedometers failing. As with any problem there can be several possible causes so try your best to determine what has failed before replacing anything.
thanks Bret, so far I have checked and I have no cruise control and the odometer has stopped of course only when the speedometer has stopped. all fuses are good and am wondering how do I tell if it is a speedometer failure or a circuit board. also how difficult is that to replace. estimate of repair would also be helpful. Thanks, ninjamom
You've done about as much diagnosing aas you can without an electrical multi-meter that measures voltage, amperage and electrical resistance.
The next step is to check the electrical signal coming from the VSS when the rear tires are spinning. If that signal is OK then the same signal needs to be checked at the speedometer to eliminate any issues with the wiring. After that it can be tough to determine whether the circuit board or speedometer is bad. It may be worth having a used instrument cluster installed if the wiring and sensor are ok.
Do you have a regular shop that you take your Volvo to?
no just bought the car used a few days ago for first time teenage driver. i believe if i pass this info. on to a mechanic friend of mine we might have a better heads up of where to start. Thanks for your help. Sure hope we can fix it. Seemed like a good choice for a teenager's first time car.
Agreed, this is a very good first car. Good luck! Make sure your teenager has the RepairPal app on their phone!
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Your car uses a Vehicle Speed Sensor (VSS) on the outside of the transmission it produces an electrical signal that tells the speedometer gauge how fast the car is going. See if when the speedometer is failing if the cruise control works (if it doesn't it's most likely the VSS or possibly a fuse that has failed), if the cruise control works the speedometer in the instrument may have failed.
thanks will give it a try! usually never use cruise control.