Turn signal problem

Discussion in 'Car Hauler and Auto Carrier Trucking Forum' started by Tropsnart, May 21, 2023.

  1. Tropsnart

    Tropsnart Road Train Member

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    I have a 2016 Peterbilt with a Cottrell headrack. The problem started as the right rear and right mid turn signals on the tractor would blink a few times then pause then blink a few times more. Now they have quit blinking altogether. I pulled the lights out checked for corrosion on the plugs, swapped the left and right side lights still no turn signal. My questions are as follows:
    Are the mid and rear tractor turn signals run together off one wire where if one doesn't work the other won't either?
    Both began blinking intermittently at the same time and pace.
    Is there a junction box or something similar for the headrack and if so where would I find it?

    Any help would be greatly appreciated.
     
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  3. JB7

    JB7 Medium Load Member

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    There is a Chassis Node with three 21 pin plugs on the left frame rail or under the driver's side under the cab. The lights for front and rear run through the node. You really need a wiring diagram. The Node may be your problem, but the part is not cheap. About $600 - $1,000 used and $1,600 - $2,000 new. What happens when the four way flashers are on? Follow the tail light harness from the rear lights forward. There will be one connection between the taillight harness to the rear chassis harness which leads to the node. You can unplug the connection there and see what the lights do. Same with the plug at the node. If nothing changes then you ruled out any problems from the node back. Unplug the input connector at the node, try the signals and see what happens. Are the light signals ok on the dash?
     

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    Last edited: May 21, 2023
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  4. Tropsnart

    Tropsnart Road Train Member

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    Those 2 lights do not flash with the 4 ways on either.
     
  5. lester

    lester Midwest's #1 Feed Hauler

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    Did you check your wires with a test light? Could be as simple as a broken ground or +
     
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  6. Tropsnart

    Tropsnart Road Train Member

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  7. Banker

    Banker Road Train Member

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    I had issues with my left side rear and mid side of cab turns on my 2016 Pete 389 Cottrell a few years ago. I found that those lights were on a separate fuse from the mirror and front turns. There is a junction box on the back side of the tractor near your hydraulic connections that Cottrell wired those and some trailer lights through. Take the catwalk off and you have easy access. My first thing I would do is run a new ground wire before I went any further.
     
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  8. Tropsnart

    Tropsnart Road Train Member

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    I saw that box yesterday when I was farting around with the lights but wasn't sure what it was for. Do you remember which fuse box the turn signal fuse was located in? I'll be back at it tomorrow morning hopefully armed with enough new knowledge to convince myself that I don't need to pay anyone to fix what would seem to be such a small fix. Electrical is definitely not my thing but the place I park at always wants to diagnose the most expensive repair right off the bat. Abs light on, needs new abs module. Headlight keeps blowing, needs new chassis computer. Truck cranks but won't start, needs new fuel pump. Abs only needed a $75sensor. Headlight only needed new $7 plug. After having my truck towed to Peterbilt figuring the fuel pump was warranty work on that truck, they put a new fuel filter on and it fired right up.
     
  9. RepoweredRookie

    RepoweredRookie Light Load Member

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    I have had 2 issues with my turn signals on my Freightliner.
    1. bad ground - lights would not blink in unison, blink slow, not blink at all.
    2. turn signal relay - lites stop blinking, and then may blink, due to owner before me (2 years prior) installing LED turns signals. Found out LED bulbs need a “grounded relay”). Fixed the issue. Not sure if that will help any.
     
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  10. Banker

    Banker Road Train Member

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    The fuse box was the one under the hood. If you get close to Indiana I have a shop that will fix your issues and they are very reasonable.
     
    Last edited: May 21, 2023
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