Head light problems...

Discussion in 'General IH Tech' started by pnwscout, Nov 4, 2018.


  1. pnwscout

    pnwscout Farmall Cub

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    Hey y'all
    I've been running around my head trying to figure out my head lights on my 79 scout II. Here is my issue and what i have done so far. So to start with I came back from deployment and when to my folks place to pick it up ( headlights worked then) so I put it on a flat bed to take to my home and when I got her home the head lights didn't work all the rest of them do. Checked power at the lamps and nothing so I went to the cab and looked at the main switch had power traced to the connector for the high beam switch had power so thought that was bad replaced the high beam switch and cable up to the connector still no power at the lamps i cant find a fuse for them or a relay anywhere. I checked all the ohms for the wires and they checked out to be perfect. Nothing goes to ground which is weird but all the other lights work.

    any help would be great
    pnwscout.
     
  2. Paul "Misterfixit" Schulz

    Paul "Misterfixit" Schulz Super Mod from Downunder Staff Member Administrator Moderator

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    The power comes via an inbuilt circuit breaker that is inside the headlight switch. Power runs from the switch to the floor dip switch, then out to the head lights which are grounded near the headlights themselves, relatively straight forward design. The wires run through a bulk head connection on the firewall but it would be unusual for both the low beam and high beam wiring to fail at the bulk head connector at the same time.
     
  3. walkersscout

    walkersscout High Wheeler

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    Stomp on he floor switch half a dozen times, that usually does it for mine.
     
  4. scoutboy74

    scoutboy74 Lives in an IH Dealership

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    With what you tested/replaced, and having nothing on high or low beam, this has to be a bad ground. Most likely nothing wrong with the dimmer you replaced. Those switches are easy to test. One feed wire comes in from the HLS. The remaining terminals are alternately hot whenever the switch is depressed. No need to guess and wonder if one is good or not.
     
  5. pnwscout

    pnwscout Farmall Cub

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    So at the high low switch you got one connector on top and two on the bottom (depending on how you look at it) so disconnect the high low switch and from top to right I have 12.57VDC and from the top to left 12.57VDC with the light switch on the dash on. Does anyone have a wiring diagram? I cant find a ground on the head light side or at the high beam switch...
     
  6. Jeff Jamison

    Jeff Jamison Lives in an IH Dealership

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    I don't remember,think the ground is at the top by the rad,but your head lights have 3 wires,one high beam,one low and the third is the ground.
     
  7. scoutboy74

    scoutboy74 Lives in an IH Dealership

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    On the pigtail for the dimmer, the circuits are as follows:
    51-16 Green is the horizontal, top slot which is the hot feed from the HLS.
    52-16 Yellow is the Hi beam output to the bulbs. A short jumper wire between 51 and 52, bypassing the dimmer, should illuminate the bulbs on Hi when the HLS is activated.
    53-16 Brown is the Lo beam output to the bulbs. A short jumper wire between 51 and 53, bypassing the dimmer, should illuminate the bulbs on Lo when the HLS is activated.
    The bulb grounds are circuit 11-16 Black and are found at the front of the vehicle in the general vicinity of the bulbs. You'll just have to look harder. Find that ground first and clean it. That may make all your troubles go away right there. You should invest in your own copy of the factory service manuals for your year of Scout, available from the Light Line Vendors.
     
  8. pnwscout

    pnwscout Farmall Cub

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    thanks y'all for the advice and got the lights fixed. it wasn't a ground problem it was a power supply problem even though i had good continuity through the wires there was a loose wire at the firewall penetration box that needed to be reset in place.
     

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  9. scoutboy74

    scoutboy74 Lives in an IH Dealership

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    Glad you got it!
     

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