Forum Discussion

djtkach's avatar
djtkach
Explorer
May 24, 2015

Diagnose electrical issues

I believe I have two related electrical problems, the second one likely self inflicted by trying to work around the first one.

Part 1: Went to pick up the TT from storage today, installed the battery (fully charged), tried the tongue jack and nothing. Connected to the TV power and still nothing at the jack. Brakes and lights on TT work.

Connected to shore power and lights and appliances in TT work, but jack is still dead. Tested jack fuse and found it is good.

After deliberating, I noticed and jumpered this, which is mounted on the frame right behind the battery box and is connected to the battery terminal:



Whatever this is, the jack worked while the two posts were jumpered. I hitched up, removed the jumper, and came home.

Part 2: Got home, re-connected jumper, expected jack to work and instead, got nothing. Connected to shore power, still no jack, and now only appliances work in TT, not lights as previously before I did the jumpering.

My guess is whatever the part in the pic is, it was wrecked at the outset of my day, and that by jumpering it I wrecked something else in the line somewhere. Any suggestions on where to go looking from here?

Thanks!!

DougT
  • westend's avatar
    westend
    Explorer
    May 25, 2015
    If the circuit breaker is indeed on the (-) phase of the battery wiring, that is a bad situation. If the breaker trips, the battery will not power the emergency brake-away system.

    I would suggest to check polarities again. The wires that are terminated at the circuit breaker in your picture show that one may have been marked with red.

    If the circuit breaker is connected in the (-) phase, you should have continuity to ground/frame. Check with battery disconnected.
  • djtkach's avatar
    djtkach
    Explorer
    May 24, 2015
    Agree with all the breaker will be replaced. It is factory original, 6yo, rusty as all say and a cheap fix.

    Westend - battery shows 12.8 when I connect it to tester on my charger, 12.? when I use my analog multimeter which doesn't have fine enough gradients to be precise.

    Wiring is as original and has one line going to this breaker (-ve), another wire (+ve) which is split into two pairs: one goes to the jack (fused), and another goes into an electrical box mounted under the frame. Jack fuse tested and fine per my multimeter. Just starting to pull and check fuses in the converter. Have not tested DC output from the converter as I didn't want to re-connect shore power given issues.
  • westend's avatar
    westend
    Explorer
    May 24, 2015
    How did you determine the battery is fully charged?
    I agree with GDE, above, the circuit breaker should be on the (+) phase of the battery wiring.

    You may have blown fuses, as was mentioned.

    What is the measured voltage at the output of the converter?
  • YC_1's avatar
    YC_1
    Nomad
    May 24, 2015
    Gdetrailer is probably right on. It is so easy to get a battery in backwards.

    That circuit breaker really needs to be replaced. It has a bunch of rust and might work with just cleaning it but it could be full of water too depending on where it is mounted. Easy and cheap fix. The part is available at any automotive supply.
  • Gdetrailer's avatar
    Gdetrailer
    Explorer III
    May 24, 2015
    djtkach wrote:
    Thanks all for such quick replies! I'm guessing either a ground at the breaker or a bad circuit breaker is the source of problem Part 1, but now for problem Part 2.

    Info as requested:

    1. Battery is fully charged - reads 12.8v
    2. Breaker is connected on the ground side
    3. Even if I directly connect the two leads versus using a jumper, the lights in the TT don't work any more when connected to shore power. Appliances still work. Previously jumping the two leads gave me jack and lights in the TT.


    #2.. WRONG, breaker should NOT be connected on the ground side of the battery.

    Breaker should be INLINE with the HOT or PLUS 12V going to the converter panel..

    You may have connected the battery backwards which will trip the breaker until the voltage is removed..

    By jumping the breaker you have most likely blown out the reverse polarity protection fuses in the converter panel..

    You will need to trace and determine the proper wiring then clearly mark the wires to prevent incorrect connections in the future.
  • djtkach's avatar
    djtkach
    Explorer
    May 24, 2015
    Thanks all for such quick replies! I'm guessing either a ground at the breaker or a bad circuit breaker is the source of problem Part 1, but now for problem Part 2.

    Info as requested:

    1. Battery is fully charged - reads 12.8v
    2. Breaker is connected on the ground side
    3. Even if I directly connect the two leads versus using a jumper, the lights in the TT don't work any more when connected to shore power. Appliances still work. Previously jumping the two leads gave me jack and lights in the TT.
  • westend's avatar
    westend
    Explorer
    May 24, 2015
    1)Your battery was probably not fully charged.
    2)Your picture depicts two wires connected to a circuit breaker, one post of which is badly rusted. Clean it all up and reconnect.
    3)It's probable that you blew some fuses, either in the distribution panel, on the converter, or both.

    Buy and use a handheld multimeter to make life simpler with your TT.
  • Bigbird65's avatar
    Bigbird65
    Explorer
    May 24, 2015
    Kevin8520 wrote:
    Sounds and looks like a bad 12 volt circuit breaker. Others will follow with additional answers.


    Notice:
    "
    Part 2: Got home, re-connected jumper, expected jack to work and instead, got nothing. Connected to shore power, still no jack, and now only appliances work in TT, not lights as previously before I did the jumpering."

    He said that he re-connected the jumper and the jack did not work. May be a bad jumper. To diagnose the problem you will have to take a voltmeter and trace the DC path from the battery to the jack. Also read the battery voltage and tell us what it is.
  • GordonThree's avatar
    GordonThree
    Explorer
    May 24, 2015
    The ground for the jack can corrode as well. Next time you're hitched pull the screws for the jack and clean the contact points between the jack and trailer.
  • downtheroad's avatar
    downtheroad
    Explorer
    May 24, 2015
    Kevin8520 wrote:
    Sounds and looks like a bad 12 volt circuit breaker. Others will follow with additional answers.


    I agree...
    Some are self re-setting, some have a button on it for re-set, some need to be replaced.
    Most any auto parts outfit will have one.

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