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nothings ever easy!!!

Discussion in 'Chevy Trucks' started by t.i.b, Mar 1, 2011.

  1. t.i.b

    t.i.b Senior Member
    Messages: 140

    so yesterday i notice that the passenger side headlight's out no big deal just get a bulb and call it a day right? nope its still out ive got popwer 2 the plug for the bulb and have tryed three bulbs. any ideas what to try next?
     
  2. RBRONKEMA GHTFD

    RBRONKEMA GHTFD 2000 Club Member
    Messages: 2,592

    Could be a ground issue for that plug. Also have you tried die electric grease?
     
  3. Ozark Hillbilly

    Ozark Hillbilly Member
    from Misery
    Messages: 53

    Does the high beam on that side work? If so then it should have ground. If not, then you probably have a ground issue.

    Otherwise if you truly have power at the connector with both ground and 12v present at the connector, your only choices are a bad connector that needs cleaning and maybe the contacts tightened up a little bit, a connector with a broken contact which will need replacing, or 3 bad bulbs.
     
    Last edited: Mar 1, 2011
  4. t.i.b

    t.i.b Senior Member
    Messages: 140

    high works fine. that means the grounds good? i've checked the bulbs on the driver side so i know its good. grabbed another tester from the neighbor its only showing 5volts on the pass and shows 12 on the driver. wish i knew that high beam = ground, could've avoided crawling around in the mud trying to find the grounds for it. thanks for the replys.
     
  5. Ozark Hillbilly

    Ozark Hillbilly Member
    from Misery
    Messages: 53

    Okay, since the high beam is working the ground wire should be good, but the ground could still be bad at the low beam connector.

    The easy way to test for that is to put the meter leads into the front side of the headlight connector until they show the +5v (should be +12v of course) you are getting with the lights switched on.

    After you show +5v that way then leave the red lead where it is and move the black lead to battery ground terminal. If it then shows +12v while grounded to the battery then you do not have good ground at the connector. If it still shows only +5v after switching the lead to the battery ground then the problem is on the positive side of the circuit.
     
  6. t.i.b

    t.i.b Senior Member
    Messages: 140

    thanks for the help hillbilly. its shoing 5volts grounded to the connector or battery. any ideas on what to check next? ive swaped fuses and the relay under the hood allready.
     
  7. kashman

    kashman PlowSite.com Addict
    Messages: 1,070

    check for 12v just before the bulb plug my be a bad plug strip the wire back
     
  8. Ozark Hillbilly

    Ozark Hillbilly Member
    from Misery
    Messages: 53

    Since the lights on the other side work then the positive side of the circuit should be good as far as any switches or fuses. You have a bad wire or connection leading to the headlight connector on that side or a bad contact at the headlight connector itself. I would recommend moving your test point to about an inch back form the connector on the positive headlight wire and see if you have 12v there. You can either just stick a small pin through the wire for contact or you can remove enough insulation to use the meter lead (either way tape it up when you are done). If the 12v is there (fairly likely) then replace or repair the connector.

    If the wire still only shows 5v at that point then it will be time to fess up with a year and model at least.
     
    Last edited: Mar 1, 2011
  9. t.i.b

    t.i.b Senior Member
    Messages: 140

    its an 02 2500hd 8.1/allison with a fisher mm2. its at 5v behind the connection and thers anothe plug about a ft back from there and i checked behind it also showin 5v there.
     
  10. kashman

    kashman PlowSite.com Addict
    Messages: 1,070

    do both of your plow lights work
     
  11. t.i.b

    t.i.b Senior Member
    Messages: 140

    ya they work
     
  12. kashman

    kashman PlowSite.com Addict
    Messages: 1,070

    well check the plow light switch in the truck
     
  13. t.i.b

    t.i.b Senior Member
    Messages: 140

    there is no plow light switch. when i plug in the plow the truck lights go off and the plow lights come on.
     
  14. kashman

    kashman PlowSite.com Addict
    Messages: 1,070

    k then id look for power at your plow light mog
     
  15. Ozark Hillbilly

    Ozark Hillbilly Member
    from Misery
    Messages: 53

    Well that sounds like the Fisher's ISO module is going to end up being the problem then. The good news is that if you want all the info you could ever need about those ISO modules you can find it in the Fisher section here. Kinda bad news too though of course since the frequency they are mentioned indicates a lot of problems.
     
  16. t.i.b

    t.i.b Senior Member
    Messages: 140

    well thanks for all the help today and i will see what i get for answers over in the fisher section.
     
  17. Ozark Hillbilly

    Ozark Hillbilly Member
    from Misery
    Messages: 53

    And if you get tired of ISO module stuff and just want to go ahead and cheat a little so you can be done with it then since both low beam bulbs combined use less than 10 amps you could just take a piece of wire and a couple of tap connectors to join the good side to the bad side. ;)

    If you got the time though, then you may want to just deal with the ISO module and not have to add any wire.
     
  18. t.i.b

    t.i.b Senior Member
    Messages: 140

    that may be the solution. theres alot of wires in that iso mod.