Shut down, key not working

Discussion in 'Kenworth Forum' started by Rev B, May 16, 2023.

  1. Rev B

    Rev B Bobtail Member

    Joined:
    May 22, 2021
    Messages:
    16
    Thanks Received:
    3
    0
    I have a Kenworth T800 with the ISX. It will not cut off with the key. It shuts down if you unplug fuel cut off on motor. With key off, it still has 12 volt power everywhere. Battery disconnect does not kill power if it is running. Only way to shut down from cab is to disconnect batteries and turn ignition to crank. That kills power to everything. Is there a selinoid somewhere that should kill power when the key is turned off?
     
  2. Rev B

    Rev B Bobtail Member

    Joined:
    May 22, 2021
    Messages:
    16
    Thanks Received:
    3
    0
    A little more info. With engin not running and ignition switch removed, I still have 12v power to everything when the batteries are connected. Is there a selinoid that should de-entergize when the key is turned off?
     
  3. Tropsnart

    Tropsnart Road Train Member

    Joined:
    Jun 8, 2015
    Messages:
    1,130
    Thanks Received:
    2,384
    Location:
    Pavilion New York
    0
    Sounds like the ignition switch itself is bad.
     
  4. Rev B

    Rev B Bobtail Member

    Joined:
    May 22, 2021
    Messages:
    16
    Thanks Received:
    3
    0
    I tested it pins when I had it out and they all show to work like they are supposed to. Same thing I thought.
    It acts like there is a relay or disconnect solenoid somewhere that is stuck.
     
    Tropsnart Thanks this.
  5. RockinChair

    RockinChair Road Train Member

    Joined:
    Feb 19, 2012
    Messages:
    5,097
    Thanks Received:
    12,851
    Location:
    CC, TX
    0
    Sounds like current is getting around the battery disconnect, and stray current may be getting into the solenoid.

    It's possible that the solenoid may be bad. And if there is a relay associated with the solenoid then that might be bad.
     
  6. Rev B

    Rev B Bobtail Member

    Joined:
    May 22, 2021
    Messages:
    16
    Thanks Received:
    3
    0
    I could see that being the cause. Where would the solenoid be that sends power to the one on the injector pump? It's strange to me that it kills the power to the pump when you turn the key to crank as well.
     
  7. RockinChair

    RockinChair Road Train Member

    Joined:
    Feb 19, 2012
    Messages:
    5,097
    Thanks Received:
    12,851
    Location:
    CC, TX
    0
    It would be a relay, not a solenoid, that sends power to the fuel shutoff solenoid. It's most likely in one of the power boxes under the hood, probably against the firewall on the driver's side.
     
    Big Road Skateboard and Oxbow Thank this.
  8. Rev B

    Rev B Bobtail Member

    Joined:
    May 22, 2021
    Messages:
    16
    Thanks Received:
    3
    0
    Thanks for the suggestion. I will look there tomorrow. Checked everything in the pannel under the dash with no luck. May have to make a trip to KW and try to see a wiring diagram. It has to be feeding more than just the injector pump solenoid though because I have full ignition power to everything (dash lights, radio, cb, ect.) Even when the engin is shut down and the alternator has no output. As soon as you connect the batteries it's like you turned the key on, even with the ignition switch totally removed.
     
  9. Big Road Skateboard

    Big Road Skateboard Road Train Member

    Joined:
    May 2, 2021
    Messages:
    6,175
    Thanks Received:
    33,882
    0
    Would agree with @RockinChair

    Sounds like a stuck ignition relay
     
    RockinChair Thanks this.
  10. Rev B

    Rev B Bobtail Member

    Joined:
    May 22, 2021
    Messages:
    16
    Thanks Received:
    3
    0
    Any idea where it might be? I called myself checking all the ones in the pannel. It does act exactly like the ignition is on. To much power for it all to be going thru the switch itself. Seems like one relay that controls a lot of multiple things.