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Brake Lights Not Working

Discussion in 'Early CJ5 and CJ6 Tech' started by GeorgeL, May 22, 2016.

  1. May 24, 2016
    GeorgeL

    GeorgeL Member

    Washington U.K.
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    Thanks Pete, you bugger.
    I'm having a diagnostic check done on Sunday on all the electrics.
    Are you an ex pat Pete?
     
  2. May 24, 2016
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    Can you please explain in detail how you performed this test? Also can you provide a picture of the brake switch?
     
  3. May 24, 2016
    PeteL

    PeteL Member 2020 Sponsor 2019 Sponsor

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    No, but 12 years in swinging London, a victim of British schooling. Mel Smith was a classmate.
     
    Last edited: May 24, 2016
  4. May 25, 2016
    GeorgeL

    GeorgeL Member

    Washington U.K.
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    I'll have pictures this weekend.
    For the test I use a 24 volt bulb in a bulb holder with two wires attached with crocodile clips on the ends..
    I attached the clips to both terminals with no result.
    At the rear end I had one clip on the bulb socket terminal, other clip to the chassis while one of my sons pressed the brake. No result.
     
  5. May 25, 2016
    PeteL

    PeteL Member 2020 Sponsor 2019 Sponsor

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    It should have lit up, so now do the same to each terminal alone, and ground ("earth") the other clip.

    One terminal should light it up, or else you have a wiring fault on the incoming (hot) wire.

    If it does light up, the fault is between the switch and the rear end.

    (Have you tested the test bulb?)

    If you simply bridge (join) the switch terminals with a jumper wire, and brake lights come on, the switch is bad.
     
  6. May 25, 2016
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    What were you actually testing for when you did this?
     
  7. May 25, 2016
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member

    Tantallon, Nova...
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    Just to be clear on the wiring- one wire from the brake switch should go to a source of power, the other should go to the lights.

    Normally the switch is open, when brakes are applied the switch closes & sends the power to the lights, the power returns from the lights by a ground connection through the body/frame back to the battery.

    If you don't see any power at the switch you need to determine where it should be coming from & check there.

    H.
     
  8. May 25, 2016
    GeorgeL

    GeorgeL Member

    Washington U.K.
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    If it stops raining I'll get up to the garage.
    Just to let you know I really appreciate your help lads.
     
  9. May 26, 2016
    GeorgeL

    GeorgeL Member

    Washington U.K.
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    Ive managed to get a mechanic/auto electrician coming on Saturday.
    He used to service/repair all my families cars and never ripped our eyes out with the bills.
    I wish I had the skills.
    Pete, Mel Smith was great, a face only a mother could love but what a great comic/actor.
     
  10. May 26, 2016
    Focker

    Focker That's what I do, I know things and I fix stuff. Staff Member 2019 Sponsor

    Tri-Cities WA
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    Watch and take notes!
     
  11. May 27, 2016
    GeorgeL

    GeorgeL Member

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    Thats my intention Focker.
    Somebody once said ignorance is bliss but its not, it just stops you fixing your own jeep!
     
    Focker likes this.
  12. May 27, 2016
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    I agree! Basic automotive electrical is very simple to understand. Quite a bit of troubleshooting can be done with a simple test light that is suitable for the voltage you have.
     
  13. May 28, 2016
    GeorgeL

    GeorgeL Member

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    My mechanic/auto electrician came and fixed the brake lights.
    The switch inside the chassis beside the brake pedal was not working but the OTHER one was!
    The second switch was on the top of the rail near the radiator.
    I hadn't spotted that one!
    As it happens the "plug" connectors were slack and vibration caused it to come out.
    Now fixed.
    Electric wipers now working great.
    What needs to be replaced are the fuel and oil pressure gauges.
    Yes the wiring was a mess!
    A couple of other little bits to do after that but I am very pleased with the work and the price.
     
  14. May 28, 2016
    Walt Couch

    Walt Couch sidehill Cordele, Ga. 2020 Sponsor 2019 Sponsor

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    Glad you got it going.
     
  15. May 28, 2016
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    X2! Sometimes it's just little things that cause big problems.
     
  16. May 28, 2016
    PeteL

    PeteL Member 2020 Sponsor 2019 Sponsor

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    Howzat!
     
  17. May 28, 2016
    GeorgeL

    GeorgeL Member

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    Chuffed !
    Now to order new bow brackets and gauges unless someone wants to gift them to me.
    Thinking about the two brake switches, would one of the be for the trailer electrics?
     
  18. May 28, 2016
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    I wouldn't think so, that should feed off of the wiring to the taillights I believe. But since it wasn't made for the U.S. it's tough to say for sure. You definitely need whatever manuals you can get your hands on.
     
  19. May 28, 2016
    GeorgeL

    GeorgeL Member

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    If I could get an operators manual for an ex swiss army cj5 it would answer a lot of questions.
    Google translate would be very busy!
     
  20. May 28, 2016
    PeteL

    PeteL Member 2020 Sponsor 2019 Sponsor

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    George, look on-line for "TM 9-8014" or TO 36A-1-401.

    Try here. Technical Manual Operation M38A1 (e.g. Wiring diagram, page 213)

    These are the US Army and Air Force numbers for the 1955 M38A1 tech manual. Not precisely the same as your jeep, but excellent info. Other related publications can be found too, for specific items, such as the engine, clutch, fuel pump, etc.

    These books are in the public domain, and no import duty to pay Her Majesty if you can find them in on-line archives. Paper prints are available from jeep vendors.

    You'll have to translate them into Swiss yourself, it's all foreign to me.
     
    Last edited: May 28, 2016

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