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light wiring problems

Discussion in 'Strobe Lighting' started by bristolturf, Dec 30, 2009.

  1. bristolturf

    bristolturf Senior Member
    Messages: 435

    ok so I took these lights that were on my salt spreader that plugged into the trailer hookup off the spreader and ran them so they would have a switch and not plug into the trailer harness. These are mounted under the rear bumper for extra lighting in back.

    I went to walmart and just bought a cheap switch, and some extra wire. I first ran the switch, one to the positive terminal and then grounded the switch to a piece of metal under the dash. Next I mounted the lights and grounded them each individually to a piece of steel under the truck. Next I ran the left side light to the switch in front of the truck, I then ran the right side wire to the leftsides wire connected the two. Went to the truck flipped the switch and nothing. I thought maybe i had a bad ground tried 3 different spots and still nothing. Any ideas on what could be wrong?
     
  2. 20Silverado05

    20Silverado05 Senior Member
    Messages: 465

    Did you use a fuse for the wire to the battery before the switch?

    If you have a multimeter then check to see if you have source battery voltage at the lights power wire with the positive lead at the lights power wire and the negative lead at the battery negative. If you read 12volts or near then try to see if your ground is good by moving the lead from the negative terminal to the lights grounds.
     
  3. bristolturf

    bristolturf Senior Member
    Messages: 435

    what i also tried doing just to see was running a wire directly to the battery and seeing if the lights powered up but nothing .
     
  4. 20Silverado05

    20Silverado05 Senior Member
    Messages: 465

    did you run just a power wire or both power and ground to see if it would power up?
     
  5. SafetyLighting

    SafetyLighting Senior Member
    Messages: 601


    So as previously asked, did you fuse the power feed at the battery? What size wire are you using and what type of switch and what is it's power rating? Start at the battery and work your way towards the lights with a meter. What type of lights are they?
     
  6. bristolturf

    bristolturf Senior Member
    Messages: 435

    yes there is a fuse on the power wire (wire from the switch to the battery). Wire size is 16 or 14, i cant remember off the top of my head. And i will have to get back to you on switch type and rating, it was just some plain switch from walmart that i picked up, nothing fancy.
     
  7. SafetyLighting

    SafetyLighting Senior Member
    Messages: 601

    ok, just be be clear, where exactly is the fuse? Is it right at the battery?
     
  8. bristolturf

    bristolturf Senior Member
    Messages: 435

    its connected to the terminal then about a foot of wire then the fuse then its ran to the switch
     
  9. SafetyLighting

    SafetyLighting Senior Member
    Messages: 601

    Ok good, just wanted to make sure. You really need a multimeter or at least a test light. How many terminals are on the switch?
     
  10. bristolturf

    bristolturf Senior Member
    Messages: 435

    three, one connects the ground wire, another connects the power wire, and the other connects the accessory
     
  11. SafetyLighting

    SafetyLighting Senior Member
    Messages: 601

    ok, well, when you turn the switch on, does it light up?
     
  12. festerw

    festerw Senior Member
    Messages: 986

    Sounds to me like the ground you've got on the lights is the problem, did you clean a spot on the steel where you grounded or just run a screw in?
     
  13. bristolturf

    bristolturf Senior Member
    Messages: 435

    then i have a multimeter, but i really dont know much about using it. where do i connect each end to so that i get a reading. I am really no expert in electric so I dont know how to do these things nor do i know how to actually even read a multimeter so if you could better explain that would be great.
     
  14. bristolturf

    bristolturf Senior Member
    Messages: 435

    yup i took a screw driver and cleaned the rust off the steel for the ground.
     
  15. bristolturf

    bristolturf Senior Member
    Messages: 435

    and no the light on the switch doesnt light up when i turn it on
     
  16. festerw

    festerw Senior Member
    Messages: 986

    On the multi tester, turn it on to the ohm setting, touch the leads together to check you've got it on the right setting and it should go to 0
    Connect one lead to one wire of your lights
    Touch the other to your ground, if it goes to 0 your all set if it doesn't you've got a bad light or a bad ground I'm guessing a bad ground the metal where you've grounded it to should be clean and shiny sandpaper works well.

    Now switch the meter to the DC volts setting something above 12 if your meter has different ranges. Connect the red lead to the + battery post and black to the - to test you should get 12.xx volts on the screen.
    Go under the dash and connect the red lead to the wire you've got coming from the battery and black to your ground, you should see the 12.xx volts again
    If you don't see 12.xx volts you have a bad connection between the battery and switch check the fuse first and verify you have the wire hooked to the 'supply' terminal of the switch and the wire going to the lights hooked to the 'load' terminal.
     
  17. SafetyLighting

    SafetyLighting Senior Member
    Messages: 601

    well, if the switch isn't working, then the lights probably won't work either. :)
     
  18. bristolturf

    bristolturf Senior Member
    Messages: 435

    ya i know that, but what was weird was when i ran a wire straight to the bat from the lights just to test them they didnt work either. So i dont really know whats going on with them. I will try that. My multimeter is old tho haha, its not digital its got the pointer and like 100000 things on the screen.
     
  19. festerw

    festerw Senior Member
    Messages: 986

    The power straight from the batter to the lights is why I suggested you clean up the grounds a little more. FWIW you can get a digital meter from wally world or harbor freight for under $10 that will do what you need it to.
     
  20. Too Stroked

    Too Stroked Senior Member
    Messages: 555

    A simple test light would probably be all you need here instead of buying a multi-meter. What you're trying to find out is if and where you have power. A test light simply needs a good ground to help you find power - if it's there at all.

    Another problem you might have is incorrectly wiring the switch - if it happens to be a lighted switch. Does your swithch have two or three connections on it? (If it has just two, disregard this whole paragraph.) If it has three, it should have a legend either molded into the case or on a sticker on the side. On lug should be from your fused / hot lead. Another should go to your lights and the third should be a ground. Get this mixed up and you won't get power where you need it.

    Another silly thought. Did you fuse blow along the way due to a problem? Your wire diameter sounds a little light and we don't even know how many amps your lights are drawing yet. If it blew right away, that would explain a few things and I've seen far stranger things happen.

    And finally, remember the advice a wise Service Manager taught me many years ago: "Almost all weird electrical problems are a bad ground."