Wipers staying on and....

[Cummins12V98]

This is for my Dad's 2012 LongHorn 2wd Dually 68rfe. His wipers will not shut off. The pics below show other issues. He did disconnect the battery cables but that changed nothing. Thanks!

 

[sag2]

He has a bus communication problem. When that happens the controllers are set to turn on the lights and wipers as a default because the truck does not know if it is dark or raining. It is a safety thing so it can still be driven. It is most likely the interior bus if the truck starts and runs. Was anything done in the last few days or weeks to any wiring? Most often it is a bus wire shorted or a bus wire pushed out of a connector. The voltage needs to be monitored on the bus to get a better idea of what is happening.

 

[Cummins12V98]

It runs fine. What is a "interior bus" ? Nothing has been done.

Thanks for the reply!

 

[mwilson]

It runs fine. What is a "interior bus" ? Nothing has been done.

Thanks for the reply!

https://en.wikipedia.org/wiki/CAN_bus

Copied from Wikipedia....

"Automotive[edit]
The modern automobile may have as many as 70 electronic control units (ECU) for various subsystems. Typically the biggest processor is the engine control unit. Others are used for transmission, airbags, antilock braking/ABS, cruise control, electric power steering, audio systems, power windows, doors, mirror adjustment, battery and recharging systems for hybrid/electric cars, etc. Some of these form independent subsystems, but communications among others are essential. A subsystem may need to control actuators or receive feedback from sensors. The CAN standard was devised to fill this need."

 

[sag2]

Your truck has an interior low speed bus communication system for non critical modules and a high speed bus for critical modules like PCM, ABS, and air bags. Bus voltage will still need to be monitored to find the problem The good news will be if it stays broken for diagnosis. Intermittent bus problems can be a real pain to diagnose.