Hi everyone. I’m trying to figure out why my speedometer will not work. I have no ABS or Brake light on. I have all new sensors In for the ABS. I’ve looked over all my wiring and I have a new ECM and PCM computer on it.

would love some advice..

 

Does the odometer count up as you drive?

 

no it just goes up and down not staying in one place. I can be doing 75 mph and it will bounce between 40mph and 55mph. And the Cruise control won’t lock in because of it.

 

OK, I'll ask again- does your odometer show that you drove a mile if you drive a mile? Or does it show more or less or nothing?
Do you have 4 wheel ABS or only rear wheel?

 

it doesn’t show anything. And I have a 4 wheel ABS

 

Does your truck have a sensor on the top of the rear differential?
If it has it, check the wires and pull and clean the sensor.