So the speedometer and odometer on the cluster of my 1998 F150 is not working. The owner before me had the VSS sensor replaced on top of the rear axle, but that didn't help. All the fuses are good. The volt meter registers voltage at the VSS sensor too. I replaced the entire cluster, but that didn't work either. I also plugged in an OBD II reader and didn't get any reading at all for speed. I need help diagnosing where exactly the problem is. Is there a test I can do that would tell me what is wrong?

4.7L V8, 4R70 transmission.


Thanks,

Will

 

There is a sensor on the drivers side of the transmisson for the speedo on 97 and 98. It has a gear on it when you get it out. you need same color gear.

 

I believe these 90s era analog odometers wear down the worm gears quite often. That’s more than likely the issue.

“1998 f150 odometer worm gears”

Google and you’ll see.

 

Well, I changed the sensor, but the speedometer still does not function. Any more suggestions?

 

now put the old cluster back in and see if it works. Analog system, so not as difficult to run down if the old cluster doesn't work. I have 3 spares in a box if you should need some parts. If the gears are worn out, buy the 94-98 Mustang gear. Much cheaper, but the same gears.

 

Put the old cluster back, and the speedometer remains broken. Okay, let me think out loud: It does not seem likely that the cluster is the source of the problem, unless both clusters suffer the exact same electronic issues. The two sensors, which read speed--by the rear axle and transmission--were replaced and register voltage. However, the OBD II does not sense anything for speed under the dashboard. On the other hand, the truck shifts gears well enough, so there is something that can sense speed. Perhaps I should check the wiring between the transmission and cluster. If you have any other ideas please respond, and it would also be helpful to suggest how I might access and test said wiring.

 

Woops