84 W900B

Discussion in 'Kenworth Forum' started by 84 Flattop, Feb 23, 2013.

  1. 84 Flattop

    84 Flattop Bobtail Member

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    The indicator light for my "fifth wheel unlocked" light stays on and regardless if its locked or not. Can someone point me in the right direction to finding the circuit for this so I can fix it.
     
  2. special-k

    special-k Medium Load Member

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    There must be a sensor on the 5th wheel. The sensor probably provides a ground for the light. If you disconnect the sensor and the light goes out the sensor has a dead short inside. If not the wire has probably rubbed through somewhere and is grounding out against the frame/body somewhere. I'm not a mechanic but thats where I'd start.
     
  3. 84 Flattop

    84 Flattop Bobtail Member

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    I'm sorry I meant to put the "fifth wheel slide unlocked". I have looked at the fifth wheel for some sort of switch but visibly I can't see one.
     
  4. Autocar

    Autocar Road Train Member

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    It is inside the dash, connected to the the valve that controls the slider.
     
  5. special-k

    special-k Medium Load Member

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    I wondered about that, never saw a 5th wheel lock light. It should be a lot easier fix now anyways.
     
  6. 84 Flattop

    84 Flattop Bobtail Member

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    Thats what i thought, I'll check their again, I tried tracing the air line off the valve and never found it. Thanks
     
  7. Autocar

    Autocar Road Train Member

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    Look on the valve, itself. Probably 3 ports on it, 1 in, 1 out to 5th wheel, 1 with switch screwed into it. Switch could have either 1 or 2 wires. 1 wire type grounds through the valve. 2 wire is 1 hot wire, 1 ground wire.
     
  8. 84 Flattop

    84 Flattop Bobtail Member

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    Only 2 air lines, in and out, that's it.
     
  9. Autocar

    Autocar Road Train Member

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    One air line will be supply, with air in it all the time. The other goes to the slide cylinder. That one will go to the electrical switch, also.
    Your '84 KW is not much different from my '84 Autocar. Same basic set up, just a normally open electrical switch, operated by air pressure. Try tracing the wires, from the light to the switch. It's in there, just a matter of finding where they hid the darn thing.
     
  10. truckmechanic

    truckmechanic Medium Load Member

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    Follow the line to the firewall it most likely runs to a manifold on either the inside ot outside of the firewall and that is where the switch will be