2nd Gen Non-Engine/Transmission No spedometer or cruise

[zeke97]

I have a '97 ctd 3500 ext. cab 4x4 with a 5spd, the spedometer suddenly does not work at all, I haven't owned this truck very long and the speed sensor looks like it was replaced recently, any suggestions would be greatly appreciated, also the cruise does't work any more, could these problems be related?



new TDR member,

zeke97

 

[rmcnamee]

I'd suspect the speed sensor or related wire harness went bad. If the speed signal is not getting sent to the computer, because of either a faulty sensor or harness, the cruise will not work. Without a signal, the computer doesn't know how fast the truck is going, hence cannot engage the cruise control.

 

[MPerez]

I don't know if this applies to anything other than a 98 but this is a possibility. The speed sensor on the transmission output housing and the RABS speed sensor on the top of the rear differential both can drive the speedometer via the PCM. If the speed sensor on the transmission fails, the speedo will still work, but it will be sluggish to start up - like for the first 15 or so MPH, then it will seem normal. If then the RABS sensor (the one on the rear axle) also fails, you get total speedo failure. Though when I encountered this condition (the RABS speed sensor failure), the ABS light on the dash lit telling me about the failure.