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D6N brakes locked. Anyone have any experience with this issue?

playdirt ยท 2013-08-20 09:42

Both brakes are locked on a D6N. I believe the problem is electrical related and was wondering if anyone has seen this problem before that could offer up any suggestions. I have the schematics for the machine (many thanks to Nige!) but was hoping to gain some insight into the issue before I head out to have a look at it. It's stuck on a job site about 40 miles away. Can anyone help? Thanks

Replies6
  1. #1Bob/Ont2013-08-20 10:22

    Take a new solenoid with you. A solenoid powered through an ECM will not have any power supply if the solenoid is open or shorted. ECM just protects it's self that way. Hope this saves you some time. Later Bob

  2. #2playdirt2013-08-20 10:59

    Thanks Bob, one solenoid controls both brakes? I also see a number of solenoids for the brakes. Park brake dump, secondary brake dump,and one just labeled brake solenoid. The first two have a different part number from the brake solenoid. Any idea on which one to take with me?

  3. #3Nige2013-08-20 11:38

    Check the wiring from the park brake switch to the transmission control. The switch has 2 inputs to the ECM (one N/O, the other N/C when the Park Brake is applied) and BOTH of them must change state when you flip the park brake switch from off to on or vice versa. Both wires go to Connector J1 on the ECM, the wire for the N/C input is F780 Pink and goes to Pin 13, the N/O input is 419 Yellow and goes to Pin 19. The common return for both wires is 975 White which goes to Pin 3 on Connector J2 on the ECM. Another thought. Does the machine have any active Diagnostic Codes..? This will be right next to the digital display for the hour meter. When they key is turned on the "SERV CODE" indicator must light up as part of the test procedure, if there are no Active Codes it will go out after the test. If it stays on you have Active Codes.

  4. #4playdirt2013-08-20 11:45

    Hey Nige, Thanks for all the info on the troubleshooting. That's a tremendous help. Not sure about the diagnostic codes but I'll be sure to take a look when I get in front of the machine. Jeff

  5. #5Nige2013-08-20 12:00

    If you have any Active Codes it may be a good bet one of them refers to the Park Brake solenoid.

  6. #6playdirt2013-08-20 12:53

    Much obliged, Nige! Thanks for all your help. I'll let you know the outcome.