Mechanics: Electrical system

Discussion in 'The Okie Corral' started by Matthew26, Jan 3, 2010.

  1. Matthew26

    Matthew26

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    I have 2006 chevy tahoe. I pulled a trailer the other day and for some reason the running lights would not work. The blinkers and brake lights worked, but not running lights.

    I hooked the trailer up to a buddies truck and everything worked fine.

    Also, I checked my fuse panel and didn't see anything there?

    What else should I check?
     
  2. paynter2

    paynter2 It ain't over Millennium Member

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    When you say running lights I assume you mean tail lights too. Generally, tail, parking, dash (running) are all on one circuit. Re-check the tail light fuse. Replace it even if it looks good.
     

  3. Bill Powell

    Bill Powell Cross Member CLM

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    Maybe your battery isn't big enough to run all the lights.
     
  4. Poppa Bear

    Poppa Bear Protective G'pa CLM

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    If you were running a flat 4 connector then you have a broken wire between the vehicles tail lights and the trailer connector. Your trailer lights come off your vehicles lights rather than a separate circuit from the fuse panel.

    Another problem could be a dirty connector on your truck.
     
  5. paynter2

    paynter2 It ain't over Millennium Member

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    Poppa Bear's post made me thing - are you referring to the 'running lights' on the vehicle or the trailer?

    Vehicle - check fuse

    Trailer - check wire to connector (as Poppa Bear said).
     
  6. Bill Powell

    Bill Powell Cross Member CLM

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    Since my battery joke didn't fly I'll try something else. Are you using a separate ground wire, or are you using the trailer ball to ground? if you are grounding through the trailer ball your truck, for whatever reason, probably is losing alittle bit of ground and your friends truck is not.

    I had a bad trailer ball ground one time and when i turned on the turn signals the headlight started blinking.

    Weak or erratic grounds can cause some really bizarre problems, including what you described.
     
  7. Poppa Bear

    Poppa Bear Protective G'pa CLM

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    4 way flat molded connectors allow basic hookup for three lighting functions; right turn signal / stop light (green), left turn signal / stop light (yellow), taillight / license / side marker (brown) and a ground (white).
     
  8. paynter2

    paynter2 It ain't over Millennium Member

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    Ha Ha - very funny joke. I thought maybe you were up too late last night... :whistling:

    Ground is everything. I used to just use the trailer ball. Then, one time I had ground problems - on the way to Canada. I threw something into the front of the boat and the problem was fixed - the pin (bolt) at the tilt was not conducting. I just cleaned things up with a little sanding and filing and we were on our way.

    Then, I used to run a wire from the trailer connector plug to a sheet metal screw in the tongue of the trailer - that was better.

    Now, I splice into the ground wire from the trailer connecotre and run a separate ground wire to each tail light. Never a problem and the lights are much brighter and easier to see in sunny weather.

    Bill, it's warming up outside! I just checked and were up to -28F. Whoopee!
     
  9. byf43

    byf43 NRA Patron Life Member

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    Maybe I missed this. . .

    Is this a 'flat' 4 wire connector, or, a 'round' 7 wire connector???

    If it is a 'flat' connector, Poppa Bear is spot on.

    If it is a 'round' connector, with a volt meter, check each connector to ground, for continuity.
    I had to replace the 'round' connector, (if memory serves me, it was called a 'Bargman' connector). One of the wires corroded inside the connector.


    7 wire:
    http://www.western-towing.co.uk/acatalog/Trailer_wiring.gif
    http://www.ligneous.com/cedar/images/bargman_wire_harness.gif

    4 wire:
    http://www.drmikesandy.com/X-H20/Trailer Wiring Diagram.jpg

    5 wire:
    http://www.jarheadjeep.com/trailer/tow_wiring/trailer_wring.jpg
     
    Last edited: Jan 3, 2010
  10. Bill Powell

    Bill Powell Cross Member CLM

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    You did have an F on the end of that temperature. Damn........................

    On my pickup the double row of clearance lights depend on the tailgate latch for a ground and when you open the tailgate you get a hell of a light show.
     
  11. MtBaldy

    MtBaldy Obie Wan, RIP

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    I can't help the OP but since the thread appears to have piqued the interest of some gearheads I'll throw out my own problem.

    I have a 2002 Ford Explorer Sport Trac. A few months ago it started having problems starting. You would just hear a "click" when the key was turned. Since that's usually a symptom of a failing battery I took it to Walmart and they put a new battery in it but because they didn't have a 750 amp hour battery they put a 650 in it. Problem continued. I finally had the truck towed to the local Dodge dealer (our only remaining dealership) and they replaced the starter. Problem continued. Dodge dealer said I had to take it to a Ford dealer to fully read the computer codes. Took it to nearest Ford dealer (30 miles away) and their computer said the problem was the undersize battery, alternator checked out ok, and I let them replace the basically new battery. Problem continued. My stepsons usually drive the vehicle but I drove it some. I noticed when it was cold the alternator appeared to work. As it warmed up at some point the voltage would drop from around 14 to 11 or 12. I looked for a voltage regulator and didn't see one. A call to Ford confirmed it has a voltage regulator built in to the alternator. Last week I had the Dodge dealer replace the supposed good alternator. I reasoned if the starter is good, the computer is good, and the battery is good, the alternator is about the last thing that could be causing the problem. It's too early to tell but the truck has not failed to start yet. The technicians at the dealerships all say it makes sense but they woudn't do it because the computer didn't find it. So, did I miss anything? Any ideas what else could be causing it not to start? Thanks.
     
  12. Rinspeed

    Rinspeed JAFO

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    You need one of these.





    [​IMG]
     
  13. paynter2

    paynter2 It ain't over Millennium Member

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    I'm not up on modern vehicles - I sold my CJ-5 and no longer work on them (vehicles). But, you've covered just about everything I can think of except the starter solenoid.

    This solenoid is just a small switch that closes (and opens) a larger switch when you turn your key to start. The small switch is driven by the key - it closes and lets much more juice flow through from the battery to the starter. Usually, the clicking you hear is the solenoid switch being activated. But, if you starter isn't turning, the solenoid switch isn't working or there is no juice going through it.

    Have a mechanic check the amperage on the output side of that starter solenoid.
     
  14. MtBaldy

    MtBaldy Obie Wan, RIP

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    Ummm, I have a couple but what's that going to find that the Ford diagnostic computer didn't?
     
  15. MtBaldy

    MtBaldy Obie Wan, RIP

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    You make a good point. I was assuming the starter solenoid was making the "click" and thus working. I also assumed they replaced the solenoid with the starter or at least checked it but that may be a faulty assumption. I guess I'll try and hunt up the paperwork and see if the solenoid was replaced with the starter. Thanks.
     
  16. RenoF250

    RenoF250

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    The diagnostic computer is not good and finding simple stuff like alternators and batteries. I would not trust if for that.

    If you found the voltage dropping it probably was a bad alternator although the new 650A battery should have started it new.

    Otherwise, I think paynter is right, probably the solenoid. There is a disc in there that gets pushed into some contacts to power the starter. It can get pitted in spots and not give a good connection and work again after it turns a bit.

    On the original topic, I would bet it was a bad trailer connection. Those connectors get nasty and then intermittent, mine is always giving me problems.
     
  17. paynter2

    paynter2 It ain't over Millennium Member

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    I don't remember if there's a ground wire from the starter to the frame. If they replaced the starter they would have a clean connection between that ground and the starter - but the frame ground may need to be cleaned up too.

    As Bill Powell mentioned above, grounding is very important and sometimes hard to diagnose.

    But, if you have juice to that starter (via the solenoid) the starter should turn. Jumping the starter would prove that. But, with a new starter, I doubt that's your problem.
     
  18. MtBaldy

    MtBaldy Obie Wan, RIP

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    Yeah, me too. I know the horror stories about dealerships but the mechanic at the local dealer is a personal friend and a deacon at my wife's church. He's very good and we trust him completely. He replaced the starter.
     
  19. RenoF250

    RenoF250

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    Usually there is a ground straight from the battery to the engine, then a smaller ground to the frame, and then another between the engine and the frame.

    I had a friend lose (look I got the right lose/loose this time) the main ground so his car would not start. Then it started smoking from the back from the engine to frame ground getting cooked.

    New starter will not help if the solenoid is not on the starter.
     
  20. MtBaldy

    MtBaldy Obie Wan, RIP

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    Thanks for the replies. Some points I hadn't thought of have been raised. I'll ask our local mechanic if they checked the solenoid and ground but I'm sure they did. It's running at least for now and if it keeps running I'll assume the alternator fixed it.