I have an F550 2017 6.7 Powerstroke with a pto on it. Last time we went to use it it was dead. I am not getting ground back to my relay. If I manually supply a ground the PTO engages but the idle speed control does not work. Any suggestions?

 

Have you contacted your local dealer or whom ever installed the PTO?

Here is the Ford bulletin on the 2017 and later SEIC. Maybe it will help you locate and isolate the problem.

https://www.fleet.ford.com/truckbbas/non-html/Q-256.pdf