Medium and Heavy Trucks
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Hi my name is***** will be glad to try to help. Do you have any fault codes logged? Is your speedo, Jake, or Parked PTO high idle working?
Check for VSS ( Vehicle speed sensor problems at the rear yoke of the transmission, park brake switch and harness/connector pins for damage on both . Let me know
Here is your engine diagram to help with testing your wiring and sensors, and switches.
Check the air pressure switches for the park brake/PTO and wiring harness. Click on this link for the chassis schematics to help.
usually they are near the brake pedal and the other is behind the dash near the maxi switches/ park brake switches. Some are on an air manifold on the newer models under the dash towards the drivers side.
Yes.Cummins Insite is usefull to see the switch status. PTO wont work unless the park brake switch is engaged. Also you need speed sensor signal both engine and road speed. Service brake switch and clutch switch will effect cruise as well along with a possible wiring problem. A scan tool that will read switch status will speed up the troubleshooting process