l8000 speedometer help needed

[bigfartter]

I have been working on the speedometer because it only seems to work when it wants to. Could it be the speed sensor on the transmission? I am stumped and dont know where else to look--fuses are fine. Is there supposed to be a constant voltage supply to the sensor? Should I try to swap the sensor out with an old one. I am not sure how they work, and the wiring in this truck seemed to be done by a shadetree mechanic. any help would be greatly appreciated!

[Davescort97]

It's probably the speed senor on the transmission. It should have 12 volts to it going in and variable voltage coming out depending on your speed. I would swap it out with another one. While you're in there clean the electrical connector to the VSS. This is maybe why it works when it wants to.

[Johnclave]

HI,
Speedometer works with the help of the sensor i think the sensor is not getting a proper supply so its better to checkout the volt