Please help me diagnose my wiring

Discussion in 'General IH Tech' started by mandi, Jan 31, 2015.


  1. mandi

    mandi Farmall Cub

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    Based upon my research there is little info when it comes to the b120 4x4 that I have. I decided to pull the entire wiring harness to ensure all connections were solid, fix exposed wires, and recondition the harness where someone hacked it.

    Most of the harness works and is intact. The areas I am having trouble with are the brake lights and the horn. If someone could help me determine where some wires should end up, I will eventually make a wiring diagram for this particular truck to share with fellow members.

    Horn system
    The wire for the horn button has been cut within the steering column. There are no numbers on the 2" strand of green wire. Where does this wire end up inside the column and does it attach to the green #25 wire listed below?

    I am assuming the delco relay next to the voltage regular (was converted to 12v) is used for the horn. Below is a basic diagram of the terminals of the relay:

    |-green #25 goes to the steering column
    |-white #26 goes to the battery + of volt regulator
    |-white #26 goes to the horn


    Brake lights
    So I have a green wire #22 coming off the headlight switch that ends up at the pressure switch on the master cylinder. From there, the other side of the switch heads back towards the steering column. This is where I am not sure where the rest of the system should be hooked up. I have another green #22 wire that comes from the rear taillight harness and seems like it should be connected to the one off the master cylinder. Would this be correct?

    Should the brake lights work without the key or headlights on?


    One last question, how many positions should the wiper switch have? There are i believe 4 wires going to the switch but I can only turn it literally 1/32 of a turn. The wipers will work with that short of a turn but doesn't seem correct.

    Thank you for all the help. I am very close to driving this truck. Waiting for a title before I will mount some fresh rubber. The seat has already been upholstered! Ill post some pictures soon.
     
  2. Albuq. Henry

    Albuq. Henry Binder Driver

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    Not sure on yours, but I am doing the same kind of repair job on my 63 scout. I see some similarities but not for sure how yours should be. On the horn, mine has a relay. Power jumps from the voltage reg. to the relay a ground signal from the horn button goes to the relay and the power jumps inside the relay to the horn to make it sound, the body of the horn is the ground.

    I also have the circuit 22 for the brakes, on my wiring diagram 22 gets power from the headlight switch it is hot all the time from there it goes to the pressure switch from the switch it goes to the turn signal switch and depending on if the light should be flashing or not it lights up either the left right or both tail lights....

    On mine I have an extra wire with 22 on it that is puzzling me, it comes out by the gauge cluster.
     
  3. mandi

    mandi Farmall Cub

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    Could you post a picture of your wiring diagram? Also which wire is ground coming off the ignition, head light switch or etc. Trying to test the harness on the bench and a little confused on where I need to hook up negative side of battery to the harness.
     
  4. Albuq. Henry

    Albuq. Henry Binder Driver

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    There are a few diagams here...
    http://www.ihpartsamerica.com/forums/electrical-tech/5408-ihc-electrical-schematic-library.html

    For the most part the ground is all through the frame/body. If you are trying to bench test you are going to have to run a ground wire from the neg batt. to each bulb or item you want to test, that will simulate the body, all the lights ground out through their mounting to the body. The way the horn relay works is power comes from the voltage regulator, this is the power for the horn and power for the relay to operate. Ground to close the relay, comes from the bolt holding the steering wheel on, a spring touches that bolt and pushes a contact/brass cap up into the steering wheel away from the other half of the contact which is connected to a wire going to the relay. When the button is pushed ground goes through the spring to the cap and the cap touches the bottom contact.
     
  5. Doc Stewart

    Doc Stewart Content Team Staff Member Moderator

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    Have you asked BinderBooks.com if they have a manual for your truck?
     

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