1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

brake lights not working still

Discussion in '6.9L IH & 7.3L IDI Diesels' started by 88beast, Mar 17, 2011.

  1. 88beast

    88beast Full Access Member

    Posts:
    2,219
    Likes Received:
    1
    Joined:
    Sep 23, 2009
    Location:
    pa
    ok now i have a new brake light switch new sockets and a new turn indicator switch
    still no brake lights
    both signals work
    and markers still work
    i need a wiring diagram or somewhere to look more in detail
    i know it goes from batt to brake light switch then either to
    turn switch
    or direct to brake lights
    i have no power at the lights or where i replaced all the trailer wiring today
    thanks
     
  2. bigblue85

    bigblue85 Full Access Member

    Posts:
    340
    Likes Received:
    5
    Joined:
    Feb 1, 2011
    Location:
    Vallonia/IN/USA
    ground. or you got a wire that the outer coating has rubbed off somewhere and is causing a ground or ohm jump from one wire to another that could have the outside wore off. is there any fuses or relays popping?
     
  3. idi traveler

    idi traveler Full Access Member

    Posts:
    768
    Likes Received:
    0
    Joined:
    Dec 13, 2009
    Location:
    Brashear, Texas
    The ground to the bed should be good because the other lights work. Are the any splices in the brake light circuit? I was working on an F150 a few weeks ago that the tail lights didn't work on it. I found three splices in the power wire(crimp style). I soldered a new piece of wire in bypassing the splices and it fixed it. Take a look, you have nothing to loose!
     
  4. 88beast

    88beast Full Access Member

    Posts:
    2,219
    Likes Received:
    1
    Joined:
    Sep 23, 2009
    Location:
    pa
    well i know from cab to lense the turn and brake work on the same wire and filiment so it got to be something in the cab but i got so many wires under there with all my mods its a nightmare plus work the po did makes it worse
     
  5. franklin2

    franklin2 Full Access Member

    Posts:
    3,848
    Likes Received:
    452
    Joined:
    Feb 24, 2009
    Location:
    Va
    The power for the brake lights leaves the fuse, and then goes to the brake switch on the brake pedal. I would check for power at the brake pedal switch. You should have power all the time(even with the key off) on one side of the brake pedal, and both sides when you push on the pedal.

    After the brake pedal the wire goes to the column and then up to the turnsignal switch. It goes into the switch as a lightgreen wire. The switch co-ordinates the brake lights with the turn lights, since they are the same thing. So if the turn switch is in the center, you should get 12v on the lightgreen going into the switch, and 12v on both the lightgreen/orange and the orange/lightblue wires which go back to the rear lights.
     
  6. 88beast

    88beast Full Access Member

    Posts:
    2,219
    Likes Received:
    1
    Joined:
    Sep 23, 2009
    Location:
    pa
    thank you thats what i was looking for so i need to check the turn switch i have 12 at the bl switch when presses
     
  7. idi traveler

    idi traveler Full Access Member

    Posts:
    768
    Likes Received:
    0
    Joined:
    Dec 13, 2009
    Location:
    Brashear, Texas
    Does the wind shield leak over the column? Mine did and it caused the po all kinds of problems, and then me. It turned out that some of the contacts in the turn indicator were corroded. A whole lot of wire repair later and then a turn switch all of my lights on my truck worked. That was over a year ago, been trouble free ever sense. I guess I'm say'n, if everything else is good, it's time for a hard look at the turn switch. $45 at O'Riely's
     
  8. 88beast

    88beast Full Access Member

    Posts:
    2,219
    Likes Received:
    1
    Joined:
    Sep 23, 2009
    Location:
    pa
    ya i just put a new switch in but im going to look into it later today hopefully
     
  9. Cainon

    Cainon Registered User

    Posts:
    38
    Likes Received:
    7
    Joined:
    Sep 27, 2019
    Location:
    Smithfield
    Did you ever figure it out? I'm having the same problem
     
  10. Cubey

    Cubey Full Access Member

    Posts:
    1,146
    Likes Received:
    220
    Joined:
    Oct 18, 2017
    Location:
    USA
    If you have a T harness for your trailer wiring, check it. It's down under the bed right near the rear bumper. Mine's wires pulled apart some, causing screwy tail/brake lights. The two connectors that plug into the T fit each other, at least on my 87 F250. I just unplugged both connectors from the T and plugged them into each other. Problem solved. I think in my case it was the tail running lights, but it's possible the brake wire could pull loose instead.
     
  11. Cainon

    Cainon Registered User

    Posts:
    38
    Likes Received:
    7
    Joined:
    Sep 27, 2019
    Location:
    Smithfield
    Thank you I'll check there
     
  12. Cainon

    Cainon Registered User

    Posts:
    38
    Likes Received:
    7
    Joined:
    Sep 27, 2019
    Location:
    Smithfield
    Checked. Not that. The po hooked up a brake control and God only knows what else. There is so many wires going to absolutely nothing its unreal. It's a nightmare under here.
     
  13. RetiringColt

    RetiringColt Supporting Member Supporting Member

    Posts:
    37
    Likes Received:
    15
    Joined:
    Mar 18, 2019
    Location:
    Washougal WA.
    Check the system like Franklin2 suggested. I would remove any add-ons done by previous owners. Also remove and repair damaged wires caused by scotch-lock type wire splices. they are a quick fix but break wire strands and introduce corrosion. In my experience I usually find the problem at a connector, the switch, or the load. Mine still worked but was really dim. I found corrosion at the round terminal between the bed and the rear fuel tank. hope this helps guys.
     
    Cainon likes this.
  14. Cainon

    Cainon Registered User

    Posts:
    38
    Likes Received:
    7
    Joined:
    Sep 27, 2019
    Location:
    Smithfield
    I have power getting to the hazard relay on the back side of the fuse panel but I here no clicking from the relay. Any ideas? It is brand new relay just bought it earlier this week
     
  15. franklin2

    franklin2 Full Access Member

    Posts:
    3,848
    Likes Received:
    452
    Joined:
    Feb 24, 2009
    Location:
    Va
    Those relays work on heat. The heat comes from the current draw of the bulbs. No bulb load it will not flash. Take the new flasher back out and make a jumper and jump the terminals out on the back of the fuse box where it plugs in. Then activate the emergency switch. All turn bulbs front and back should be on solid. If they are out or some are not working, that is why the flasher is not working.
     
    Cainon likes this.

Share This Page