Trailer brake lights not working

Discussion in 'Trucks and Trailers' started by RollTide, Jul 18, 2014.

  1. RollTide

    RollTide LawnSite Member
    Posts: 88

    I guess I'll take that module to advance auto and see if they can match it.
     
  2. dieselss

    dieselss LawnSite Bronze Member
    Posts: 1,548

    Do you have brake pwr going into that module?
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  3. RollTide

    RollTide LawnSite Member
    Posts: 88

    I have no idea. Don't know which is brake power.
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  4. dieselss

    dieselss LawnSite Bronze Member
    Posts: 1,548

    So test light it like I suggested 1 page ago
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  5. RollTide

    RollTide LawnSite Member
    Posts: 88

    Adding a new wrinkle to the situation. There is another connector above the spare tire. There is a plug connected to it and it runs back toward the cab and terminates between the cab and bed. Someone cut it off and taped it up. There is also a connector in the bed of the truck between the wheel well and tailgate. If these terminated wires went to the bed connector why was it ran to and cut off between the cab and bed? Gonna see if there is power to those wires. This wire cluster aslo has 8 wires. The normal 7 and then a black. Would that just be bolted to the chassis?
     
  6. RollTide

    RollTide LawnSite Member
    Posts: 88

    Ooops. Sorry. I do not have a black wire. That was a large blue wire.
     
  7. RollTide

    RollTide LawnSite Member
    Posts: 88

    Found this on a Chevy forum.

    "I wish I could wager on this one.

    You will need to replace the flasher (turn signal) module.

    Follow my logic.....
    The turn and stop for either trailer taillamp share the same wire and fuse (on the truck), and turn is working. Stop lamps on the truck are working, but not on the trailer, however, there is only one set of stoplamp contacts used for brake lamp activation (so stoplamp switch failure would mean no brake lights, anywhere).....

    If you carefully examine your truck taillights, in action, you'll notice that the turn and brake filaments are actually two seperate bulbs, and your trailer has turn and brake combined in the same filament. How'd they do that??? The flasher module contains the logic circuit that let's brake and turn down the same wire without letting brake voltage back into the turn circuit (Your front turn signals would glow bright upon every brake application if the were no logic circuit in the module)."

    This just may be my problem since my hazard flashers don't work even after replacing the relay.
     
  8. whiffyspark

    whiffyspark LawnSite Fanatic
    Posts: 6,088

    Those wires are probably for 5th wheel
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  9. RollTide

    RollTide LawnSite Member
    Posts: 88

    whiffyspark, they are. I just wonder why they routed them the way they did. It was strange. Anyway, I think I may have solved my problem. Gonna order the turn signal switch and replace it. I wouldn't think that was it except that my hazards don't work.
     
  10. whiffyspark

    whiffyspark LawnSite Fanatic
    Posts: 6,088

    Hazards go through switch if I remember right. Find a schematic and double check
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