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acker1's avatar
acker1
Explorer
Dec 13, 2015

trailer wiring

Not quite an RV question, but--I'm volunteering at a Fl state park. We have decorated a tram to use as a float in a local parade. When checking the turn signal & brake lights on the tram I am having a problem. Tow vehicle is a Dodge Ram. Checking the connection on the Ram they all check Ok. Hooking up the tram when turning on either turn signals I get both lights flashing on tram & Ram. Tram lights are weak. I replaced the ground on the tram and the connection on the Ram. (Ram lights work OK when not hooked up). I think I'm getting feedback somewhere but don't know where to start--Ram or tram? Any ideas? (Parade is tues late afternoon)

Thanks
DICK

8 Replies

  • acker1's avatar
    acker1
    Explorer
    Dec 15, 2015
    Checked all the wiring and could not find anything wrong. Found a site that gave some troubleshooting info. Whoever first wired it hooked the ground wire to the aluminum housing on the part that goes over the ball. Site stated that it shouldn't be that way, it needs to be on the frame instead. Moved it to the frame and it works very well. Very bright also.

    Thanks to all for the helpful hints!!!!!!!!!!!!!!!!!
    DICK
  • acker1's avatar
    acker1
    Explorer
    Dec 14, 2015
    Thanks for the replies. My thinking was ground also. I'll check all the above advice when park mgr get back with the truck. I'll also let you know the results.

    Thanks again,
    DICK

    On edit: It is 4 pin.
  • wnjj's avatar
    wnjj
    Explorer II
    Dec 14, 2015
    Ditto what others have said about a bad ground. The turn lights can feed across sides via the shared tail light circuit and cause both to flash, dimly.
  • dougrainer's avatar
    dougrainer
    Nomad
    Dec 14, 2015
    Remember----The hitch ball is NOT an adequate ground. Make sure the ground wire in the TRAM is installed in the receptacle for the plug and IS grounded to the frame of the Tram. I doubt the ground on the tow truck is not installed correctly. To verify ground issues is simple. Take a jumper cable and connect one end to the truck frame and one end to the Tram frame. If the issue goes away you have that ground wire problem. The other issue if not a ground is HOW the Tram tow end plug is wired. Odds are it is NOT wired to code and correct. Doug
  • enblethen's avatar
    enblethen
    Nomad
    Dec 14, 2015
    Use a set off jumper cables or pieces of wire to test trailer.
    Connect cables/wire to good battery insert wires into each pin, with ground connected to trailer, test each function.
    This will tell whether it is trailer or truck.
    Could even start by connecting truck to trailer ground with jumper cable.
    Yes, it sounds like a back feed. You may also remove taillight bulbs one a time to see what changes with the rig hitched to truck.
  • fitznj's avatar
    fitznj
    Explorer
    Dec 14, 2015
    90% of trailer light issues turn out to be bad grounds.
    Ground each light fixture to the trailer with a separate wire;
    (you can do this temporarily using a wire with crocodile clips to verify)

    Trailer lights usually use the nuts holding the light as a ground - which corrode over time.

    Also check the white wire is really grounding - use a multimeter to verify.
  • westend's avatar
    westend
    Explorer
    Dec 13, 2015
    You probably have a light fixture back feeding another fixture. Check to make sure all your lamps are wired with the correct phase.

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