Forum Discussion

suprz's avatar
suprz
Explorer
Jun 14, 2017

Weird aux light issue!

This is on a 2006 Ford E450 chassis. I have a motorcycle carrier that I had some cheap magnetic towing lights on, on our last trip, I noticed that all the lights worked ( turn, brake,hazards, except the running lights... I figured that it was the 7 to 4 pin connector because I had the same problem while using my jeep towing a UHaul trailer. So now, I got some new LED lights, wired them up, AND got a new 7 to 4 pin connector, and I have the same issue! Now here's where it gets really weird... I checked the adaptor with a voltmeter and all the pins are fine! I checked the adaptor by itself plugged into the motorhome with the voltmeter and again all pins get power except the running lights... So I check the new adaptor on my jeeps 7 pin socket and get the same results! Everything but the running lights! So, I know the adaptor is good, I know the carrier light wiring is good too... So am I supposed to believe that two separate vehicles have exactly the same issue? I checked the 7 pin on the motorhome, and get no power to any of the pins when the running lights are on. Thoughts?? (all the lights function fine on the motorhome)
  • Sam_Spade's avatar
    Sam_Spade
    Explorer
    Jun 14, 2017
    YOu need to check the grounds in the connectors.

    IIRC, there are TWO pins that are supposed to be ground.
    BOTH are supposed to be used for increased reliability; a cheap and dirty installation might use only one. If the next guy cutting corners decided to use the OTHER one.....you have a bad ground.

    And yes, some of the lights will work without a good ground, sometimes.
  • MEXICOWANDERER's avatar
    MEXICOWANDERER
    Explorer
    Jun 14, 2017
    "I checked the 7 pin on the motorhome, and get no power to any of the pins when the running lights are on"

    I cannot think of a better place to start fixing things than right there
  • RoyB's avatar
    RoyB
    Explorer II
    Jun 14, 2017

    Google image

    Most often these are ground issues when they get to doing wierd things...

    ETRAILER is a good place to goto to look at wiring diagrams etc...

    Roy Ken
  • suprz's avatar
    suprz
    Explorer
    Jun 14, 2017
    I got under the motorhome and followed the wires for the 7 pin, and it comes out from behind the drivers side rear tail lights. So it looks like I will have to pull the entire tail light assembly to check how the wires are attached and see if the brown wire is not connected etc...
  • enblethen's avatar
    enblethen
    Nomad
    Jun 14, 2017
    Many Fords have fuses for the trailer connector. Check your owner's manual if you have one.
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    Jun 14, 2017
    This was on a car, not being towed, and not an RV but I got stopped for no tail lights.. Sure enough they were not working.

    I traced teh fault to a connector It was in a place where wheels tossed water up and it was SUPPOSED to hit a plastic panel but the panel was cracked so it sprayed all over the connector.. Result.. I bypassed every pin on that plug with soldered jumper wires and sealed them.

    Later I had a problem with my Freezer. it runs on 12 volts normally (120 volts when I have to) Well it was not being fed.. Voltmeter showed 11.something when no load droppign to zilck undewr load.. Problem was in a wire.. Thankfully there is but one wire between the battery and the test point.

    I sliced out the bad part. soldered in a jumper and sealed it.

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,188 PostsLatest Activity: Jan 17, 2025