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4 port iso module

Discussion in 'Fisher Engineering Discussion' started by nepagearjammer, Feb 27, 2011.

  1. nepagearjammer

    nepagearjammer Member
    from nepa
    Messages: 44

    installled my new wiring harness I was waiting for from fleabay...now no headlight(no low beam) on drivers side w/ plow off. flip plugs 3&4 and passenger side dosent work(low beam). are these iso modules repairable or is it junk? 4 port
     
  2. 06Sierra

    06Sierra PlowSite.com Addict
    from Maine
    Messages: 1,329

    Is the high beam on when you don't have low?
     
  3. nepagearjammer

    nepagearjammer Member
    from nepa
    Messages: 44

    yes high beams work as they should. looking on e-bay I see the words 'not serviceable' on the module. when I flip plugs 3&4 drivers side works and passenger side dosent(so wiring is ok)... may just jump plug 4 low beam output to plug #3 low beam output.
     
    Last edited: Feb 27, 2011
  4. 06Sierra

    06Sierra PlowSite.com Addict
    from Maine
    Messages: 1,329

  5. nepagearjammer

    nepagearjammer Member
    from nepa
    Messages: 44



    was set up for pos ground...changed to neg. ground(no good) and back to pos. ground(still no good). will bust out meter to check output from module..joys of buying used stuff!!! GRRRRR!!!
     
  6. 06Sierra

    06Sierra PlowSite.com Addict
    from Maine
    Messages: 1,329

    I know what you mean. I bought my plow used and when I first hooked it up I only had high beams. The highs stayed on all the time. Once I finally got smart and started looking at the little stuff I found the wires were reveresed on the plow harness, where it plugs into the headlights. Let us know what you find out.
     
  7. buddymanzpop

    buddymanzpop Senior Member
    Messages: 601

    What make and model year is your truck? What are the part numbers on your #3 and #4 port harnesses?
     
  8. nepagearjammer

    nepagearjammer Member
    from nepa
    Messages: 44

    90 k3500

    harnesses #26360 and 26361. white label iso module


    hb3/hb4 h.light system
     
  9. abbe

    abbe Senior Member
    from RI
    Messages: 719

    Is there a configuration plug? do you have it setup correctly
     
  10. nepagearjammer

    nepagearjammer Member
    from nepa
    Messages: 44

    tried that already...thanks


    set up for positive ground
     
  11. nepagearjammer

    nepagearjammer Member
    from nepa
    Messages: 44

    did a little more digging today...left low beam is not getting a ground from the iso. going to check continuity of configuration harness tomorrow...will keep you posted on what I find.

    BTW I stopped in @ a advanced auto store and asked to buy a continuity tester and got that blank stare, they will hire anyone today!!!
     
  12. buddymanzpop

    buddymanzpop Senior Member
    Messages: 601

    Do you have a configuration plug or just the dust cover plug in the control harness?
     
  13. nepagearjammer

    nepagearjammer Member
    from nepa
    Messages: 44

    configuration plug
     
  14. buddymanzpop

    buddymanzpop Senior Member
    Messages: 601

    Take it out and see what happens with out the plug, GM's don't require the use of one.
     
  15. buddymanzpop

    buddymanzpop Senior Member
    Messages: 601

    I could be wrong those 1990's models may have used the config plug. See what hppens with out, my 04's have no configuration plug.
     
  16. nepagearjammer

    nepagearjammer Member
    from nepa
    Messages: 44

    well ruled out a bad iso... bought a used one from e-bay and still have same problem...but I'm puzzled I have power to the 'low beam out' terminal 'E' of plug. Will have to trace all the wires in this harness...wire must be crossed somewhere. when schematic says' low beam in' does that mean in from vehicle harness. I'm thinking the 'A' and 'E' terminals are crossed @ the harness adapter.
     
  17. 06Sierra

    06Sierra PlowSite.com Addict
    from Maine
    Messages: 1,329

    I think that is how it works with low beam in. A should be a yellow wire and E should be orange.
     
  18. nepagearjammer

    nepagearjammer Member
    from nepa
    Messages: 44

    yea, but shouldnt I have power on the yellow wire terminal 'A' should be the 'in' from the truck...so how can I have power on the 'out' low beam if no power is comming 'in' on the yellow wire. heavy rain outside now going to trace all wires...will keep you posted.


    also changed configuration plug to a negative round.
     
  19. NHresident

    NHresident Senior Member
    Messages: 285

    you got the wrong head light cables 26360+361 are for 99-02 GM's for ur 90 u need cables 26351+352 and u dont need a config plug AS LONG as u have 4 head lights total IF u only have 2 headlights total u need a 3rd different set of headlight cables 26353+26356 and with these U WILL need the cofig plug