No Brake or Turn Lights

Discussion in 'Etrailer.com Trailers and Towing Forum' started by mcginnis101, Jun 10, 2018.

  1. mcginnis101

    mcginnis101 New Member

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    Jun 10, 2018
    I have a 2007 Toyota Tundra with the factory tow package. I have always pulled trailers with no issues. But now all of the sudden I have no trailer brake or turn signal lights on any trailer. One of which has brand new wiring. I can use a volt meter with out a trailer attached and the 4 way and 7 way both have 12 volts when the brake is applied or the turn signal is turned on. But as soon as I plug a trailer in the circuit goes dead. If I unplug the trailer let off the brake wait a few seconds and test with the meter I have voltage again but as soon as I plug in a trailer dead again. Anyone have any ideas? I have traced wires checked connectors and can’t find anything. Thank you in advance.
     
  2. eoleson1

    eoleson1 Well-Known Member

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    Jul 5, 2011
    Macomb County Michigan
    Bad ground on the truck maybe?
     
  3. mcginnis101

    mcginnis101 New Member

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    Jun 10, 2018
    Do you think that I should cut the factory ground at the back of the plug and make my own ground to the frame?
     
  4. eoleson1

    eoleson1 Well-Known Member

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    Jul 5, 2011
    Macomb County Michigan
    I wouldn't recommend cutting anything just yet. Can you check continuity between the ground on the truck plug and the truck frame?
     
  5. mcginnis101

    mcginnis101 New Member

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    Jun 10, 2018
    I tested continuity and it was reading 002. With a pretty strong beep on the meter.
     
  6. joet

    joet Well-Known Member

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    Mar 16, 2011
    Elkins WV area
    Take a jumper cable and hook it to the truck and trailer frames. sounds like a bad ground
     
  7. mcginnis101

    mcginnis101 New Member

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    Jun 10, 2018
    Ok I’ll give that a shot tomorrow and let you all know what I find out. Thanks for the help so far.
     
  8. nineoaks2004

    nineoaks2004 Every meal is a picnic and every Day is a holiday

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    Oct 15, 2006
    Graceville, Florida
    Sounds like a bad (or broken) ground, the turn and brake lights use the same filament on the bulb.
     
  9. Katskamper

    Katskamper Active Member

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    Nov 21, 2015
    Fort Worth, TX
    mcginnis101,
    see my post on no turn signal.
    i have a 1996 toyota T100& mines not working either!!
    tested fuses, did all kinds of test on camper.

    taking to uhal in morning.
     
  10. mcginnis101

    mcginnis101 New Member

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    Jun 10, 2018
    Ok folks tonight I did a dedicated ground from bare frame to trailer and also did a bare frame to the truck trailer plug ground. Still the exact same symptoms. Keep the suggestions coming. I’ll try anything.
     
  11. nineoaks2004

    nineoaks2004 Every meal is a picnic and every Day is a holiday

    3,933
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    Oct 15, 2006
    Graceville, Florida
    If the vehicle has YELLOW turn signals you need a taillight converter, wally world has them the reason is American made use the same filament for both brake and turn signals. If it has Yellow lens for turn signal it uses a separate bulb, the converter makes the signals work as American wiring. I installed a lot of them when I worked at N.A.S. Cecil Field F rec. services
    I took care of all the rental equipment it was a regular thing to install and only took a few minutes to install.
     
  12. jnc

    jnc Welcome from New Hampshire

    Are you positive that the Truck Ground is good?
     
  13. Fbird

    Fbird Active Member

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    Sep 10, 2017
    Ferndale MI
    Continuity check doesn't tell you much do a voltage drop test. Use a old round or rectangular headlight as a load. File attached explains the test. One good strand in a wire will make a wire pass a continuity check but won't be sufficient for a load. N something like a headlight the drool should be under 250 MV on the ground and under 400 MV on the positive wire. The lower the reading the better .
     

    Attached Files:

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