Been having some issues with my speedo lately. About two months ago I was getting the dead speedo and no OD so I changed out the VSS Sensor and it seemed to fix everything. Now, starting out two weeks ago and getting worse, it is jumping around everywhere. Going 60 it bounced between 70-90 and it seems like the odometer is in time with whatever reading it is showing. If I rev the truck up in park the speedo will go up to 80 and the odometer will keep on rolling.

Any suggestions? Was reading through some of the past posts and I saw that some people had issues with grounds, where are the grounds to check? My battery cables are pretty toast and I just got new ones from Mopar, guess I will change them out today and see if that helps.

 

Remove the connector on the VSS sensor. Use your volt meter to determine which wire is ground. Cut the ground wire and run a new ground wire to a known good ground.

I just did this on my truck last week. I ran my new ground wire up into the engine compartment and grounded it on the fender well. I would have ran a short ground to the frame, but I figured with all the road grime and moisture it would see, that it corrode over time.

 

The VSS has a tendency to loosen up, several guys have had them fall off. Check to see if it's tight before you do anything else.

 

VSS is tight. Where does it ground? Under the dash? I of course do not have a service manual with wiring diagrams. Would like to fix the ground if possible before cutting up my wiring harness.

 

It's grounded through the PCM.