1994 digital mileage counter blank

[Figor]

So I have a few things going on and I think they are electrical related. First the mileage counter , which is digital, is no longer showing anything.

Second the tranny is shifting hard. Are these two issues limp mode?

What kind of computer is on this truck? I checked fuses and don't see anything blown.

Thanks

 

[DaveBen]

They have micro chip computers. Sorry no Windows 10 or other similar types of computers. I would look at the dash lights for a clue as to what might be blown.

 

[Nero]

Yes they could be related, how the logic works is the engine speed sensor signal gets sent to the speedometer, and then the signal gets sent out to the TCM or transmission control module. If the speedo is acting up, it very well could not be providing the engine speed signal to the TCM and causing hard shifts. Is your O/D light flashing at all?
The TCM is located in the left kick panel.

 

[Figor]

No lights flashing. No idiot lights on. Good info there. That makes sense to me. I'll be looking at that engine speed sensor. Is it on the crank?

 

[DaveBen]

It is on the rear of the tranny or on the rear differential.

 

[Nero]

It is on the rear of the tranny or on the rear differential.

That would be the vehicle speed sensor.

The engine speed sensor is on the injection pump housing, right on top.

@Figor since you don't have the odometer lighting up, I would be more inclined to say you are having a cluster issue, or an issue with power to the cluster.

Do any of your other cluster lights work? Like does the check engine light come on at initial key on, blinkers work, ect?