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Dim Nighthawk lights

Discussion in 'Western Plows Discussion' started by probee, Dec 9, 2011.

  1. probee

    probee Member
    Messages: 37

    I just put a new set of Nighthawk lights on my mvp ultramount,3 port module. My low beams seem dim and high beams are fine. Any suggestions how to get more light from the low beams?

    Have a ultramount undercarriage I just took off a 2008 gmc 2500 hd for sale.

    Thanks
     
  2. Andrew010

    Andrew010 Senior Member
    Messages: 205

    I have the same problem and never could figure it out. I have 12 volts at the light.

    Same plow is now on a different truck and have the same problem as well. It's something in the ISO module or plow itself. Just can't figure out what exactly.
     
  3. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    I would isolate the problem by doing a voltage drop test at the light plug inside the nighthawk. First turn your lights on and put a voltmeter negative on the hot side of the light plug and put the + probe on the truck battery + post. This will show the voltage drop on the + curcuit. Then switch the leads and do the same test between the common ground at the light and the negative battery post. You should have well under one volt showing in both cases. Now do the same with the other beam activated. On the low beam (which you say is dim) might show a voltage drop but if it doesn't then I would suggest that the voltage is fine but your two fillaments are running in series when low beam is activated. That means that you common ground is on the wrong pin somehow and power is going through the low beam and the high beam fillament as the same time doubling the resistance and dropping the current.
     
  4. probee

    probee Member
    Messages: 37

    Thanks for the advice,will try try that tomorrow. Have you seen a common ground on the wrong pin before? Would that mean I would have to replace the trucks light harness?

    Thanks
     
  5. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    I have seen numerous misswiring problems from Western, never this particular issue but it is certainly possible. First I would verify that this is in deed the problem and then see if you can get the pins moved without damaging them. If it is a problem changing them I would call the dealer and ask if you can exchange the cable. You shouldn't need the truck side harness but it is possible that the problem is on that side. The cable that comes from the three port iso module could be misswired. It will be either that or the nighthawk harness that goes from the grill plug to the lights on the plow. I would suggest testing the wires and comparing them to the schematic to determin which cable is wrong. If this is actually the problem and you switch the pins at the light bulb but the actual problem is on the truck cable then when you try to use your plow on another truck you will have problems again. Here is a link to the electrical schematics manual, look on page 17 for your system. http://library.westernplows.com/ddcommon/dd_pdf/pdfs/22373.07_110108_for_web.pdf