Coronado / Trailer light issues

Discussion in 'Freightliner Forum' started by Emil Baran, May 4, 2021.

  1. Emil Baran

    Emil Baran Light Load Member

    57
    4
    Mar 9, 2016
    Cleveland,Ohio
    0
    A month ago I ripped my airlines and cable , fixed it and yesterday I replaced the whole set of airlines and green Power cable set as one.

    Last 8-9 days I have been getting this weird issue which I thought was due to old , possibly damaged cable.

    Issues:
    - ignition on ,when I press brake pedal, truck,trailer turn signals light up
    - ignition on, using left turn signal - when applying brakes , left side of the truck n trailer stop flashing and lights up , staying constantly on. Also turn signal on dash lights up.


    -ignition off, when I tap the brakes , trailer ABS light does it's cycle check
    -ignition off ,ABS ( on top of the left side light issues) blinks together with turn signal.
    - when turn signal is on ( no brakes applied) rear trailer market lights also flash.

    - hazards ON, brake pedal applied, lights stop flashing and stay constantly on

    I tried replacing the STAY-DRI trailer power outlet, nothing , then switched it to a truck side , same thing happens. I spread the prongs to make a better contact. NO ABS lights on dash and it cycles as it should on start up.

    When I disconnect the cable from trailer , truck side works as it should.

    I might add that one relay from fuse box ( one that Clicks when brakes applied) was buzzing last week Thursday everytime I Pressed the brake pedal, it stopped after 30min or so. I tried switching the relays with no luck of fixing the issue.

    2016 Hyundai Van
    2020 Coronado
     
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  3. Joyce's Volvo

    Joyce's Volvo Light Load Member

    57
    65
    Jun 28, 2016
    0
    Sounds like trailer isn't getting ground, with out a ground , power will back feed through another circuit , not enough ohms to make the flasher work for the signal circuit, markers are pulsating with the signal or brake ? You may have broken ground on tractor or trailer plug. Try hooking a set of booster cables from frame to frame making sure of contact and see what happens. Just because you put a new pigtail line on don't mean that it's all connected , they may have left the ground loose.
     
  4. Emil Baran

    Emil Baran Light Load Member

    57
    4
    Mar 9, 2016
    Cleveland,Ohio
    0
    Connected another truck to a trailer and it's a same issue. I bought the whole new pigtail that goes inside the trailer , still the same issue , I give up
     
  5. Joyce's Volvo

    Joyce's Volvo Light Load Member

    57
    65
    Jun 28, 2016
    0
    Don't let it whip you, did you try the cables frame to frame for ground? I've had similar issues, it was ground problems. As I understand , you hook to another trailer and all is well, hook different tractor to this trailer and lights go squirrelly ? If so , you've isolated the problem to this trailer. Trailer ground wiring is grounded more than one place but, that doesn't mean that all or any are getting good contact.
     
  6. Emil Baran

    Emil Baran Light Load Member

    57
    4
    Mar 9, 2016
    Cleveland,Ohio
    0
    When I connect trailer to another truck ( same model year etc) same issue happens which is when you step on the brake pedal left turn signals light up and stay lighted l. Also three of my brake trailer lights and top rear marker lights on trailer act as turn signal. ‍♂️
     
  7. Joyce's Volvo

    Joyce's Volvo Light Load Member

    57
    65
    Jun 28, 2016
    0
    Only other option that I have for you is to , look for a inline junction box on the trailer or at the back. Those are installed to reduce exposed wiring splices , supposedly water tight to keep down corrosion in the box, seals go bad and fills with water and then get lots of issues similar to yours . Hopefully , someone has had this come up before and give you better info than I . I'm running out of suggestions! Except unhook all wires from trailer pin connection except ground and hook them back up one at a time and try it until it starts doing something squirrelly .
     
  8. baha

    baha Road Train Member

    3,715
    2,277
    Jul 25, 2013
    ga
    0
    Try taping all the tail lights and center turn sig. lights with a rubber Hamer to see if you have a shorted out bulb with the 4/ways on and you can find the one that's shorted out, Buy a new male plug for the pigtail it the sits under back of sleeper and gets road salt in it all winter and keep in your tool box, if you ever have it you change it look for green corr. on them and cut them back a bit till you find clean wire and put all wires back in ck. the ground wire?
     
    Last edited: May 21, 2021
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