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Headlight question

Discussion in 'Fisher Engineering Discussion' started by BALLOONBURSTOFF, Feb 18, 2009.

  1. BALLOONBURSTOFF

    BALLOONBURSTOFF Junior Member
    from Mass
    Messages: 7

    I've been reading alot of posts on headlight problems trying to find troubleshooting tips but have not had too much luck.

    Recently installed a MM1 setup in a 98 Dodge Ram. It is the two relay setup. The harness was previously in a 2001 Ford F-150 and worked fine.

    The Low beams will not come on when the plow lights are plugged in. I can hear the relay click when I plug it in. I tried a couple different relays with no luck.

    The high beams work.

    Here's where it gets interesting... I unplugged the black (low beam wire) from the relay and applied 12volts to the wire and the lights lit up so I know there is not a problem with that wire.

    What I am not understanding is the #87 terminal on the low beam relay where the black wire plugs in does not have +12v when the plow lights are plugged in. My power probe is showing the terminal is a ground and when I apply +12v to the terminal it pops the breaker in the probe. According to the wiring diagram this terminal should NOT be a ground. Any thoughts?
     
  2. Crash935

    Crash935 2000 Club Member
    Messages: 2,377

    Heres the problem, the cross harness from the Ford is for the HB5 bulbs in the headlights, the Dodge runs HB1 bulbs in the headlights.

    Yes there is a solution. Unplug the plow harness at the back of the headlight on both sides of the truck. Remove the tan keeper on the back of the blue plug and using a paper clip, come in from the front of the plug and pop the keeper tab for the wire terminal inside the plug on the blue and orange wire. Swap the positon of the blue and orange wire on both blue plugs. Now find the black plug end on the drivers side that plugs into the factory harness and do the sme with that. Everything should work right now.
     
  3. BALLOONBURSTOFF

    BALLOONBURSTOFF Junior Member
    from Mass
    Messages: 7

    Wow. Would have never known that. Thanks. I'll try that.
     
  4. Crash935

    Crash935 2000 Club Member
    Messages: 2,377

    They just switched the low beam and ground legs around in those bulbs so your just switching the harness to match.

    Use a heavy paper clip and go down the little square cut out just under the terminal end. Push in slightly on the wire, insert paper clip then give a slight pull. Might take a couple times to catch the keeper just right.
     
  5. terryzz

    terryzz Junior Member
    Messages: 9

    MAYBE,,? follow the wires that are the (+) for your parking lights, I think that's the one that activates the LOW BEAMS , Make sure it's hot and good connections/ no shorts. I'm goin by the way my 100 year old chevy/MM IS WIRED.
     
    Last edited: Feb 19, 2009
  6. Crash935

    Crash935 2000 Club Member
    Messages: 2,377

    He just needs to flip the harness, on had HB1's the other has HB5's. I do it to harness's all the time.
     
  7. BALLOONBURSTOFF

    BALLOONBURSTOFF Junior Member
    from Mass
    Messages: 7

    Ok, switched the wires at both headlight connectors and the driver side factory headlight connector that attaches to the black plug. (The factory headlight connector wire colors were purple, red and black. I switched the purple and red. Hope that is correct.)

    I seem to be getting close but still have some problems.

    With the headlight wires switched the way you instructed, whats happening now is the low beams on the truck side are dim and the high beam indicator on the instrument panel is lit up (without high beam switch activated).

    As soon as I plug in the plow lights, they come on (not sure if high or low beam). But now the high beams on the plow lights do not activate when I hit the high beam switch.

    Sounds like a ground problem to me. Do I need to change relay connections?
     
  8. BALLOONBURSTOFF

    BALLOONBURSTOFF Junior Member
    from Mass
    Messages: 7

    Well, looking at the wiring schematic, and reading a couple other posts, the blue wire is the ground for both headlights. So, the blue wire needs to be connected to the ground wire at the factory headlight harness right?

    I think the problem might pertain to which wires I switched around on the factory headlight connector. The only thing I need to determine is which wires on the factory headlight connector are high, low and ground. One of them is black so I'm assuming that is ground and the way it is connected right now the blue wire does NOT line up with the black wire.

    Just a thought. I will confirm which wires are what. But in the mean time if you have any other ideas please respond. Thanks so far!
     
  9. Crash935

    Crash935 2000 Club Member
    Messages: 2,377

    Blue wire needs to match factory ground wire.