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LIKE2BUILD's avatar
LIKE2BUILD
Explorer
Oct 04, 2016

Reverse Lights for Trailer- RAM OEM wiring

Does anyone know if the OEM 7-way plug wiring harness on a newer RAM 2500 ('13+) has a wire for the reverse lights? If so, do you have any tips on getting that connected to the center prong in the bumper mounted receptacle?

My bass boat trailer has a reverse lockout solenoid for the hydraulic surge brakes. I would like to get the reverse lights connected to the middle prong of my 7-way connector so this feature will work. I'd love to have this operating because I can definitely feel the brakes fighting against me as I back the trailer into it's parking place at home.

I could certainly run a dedicated wire from one of the reverse lights and connect that to the 7-way. But, if there is already an OEM wire it should just be a matter of making the right connections.

Thanks,
KJ
Tow Vehicles
  • LIKE2BUILD's avatar
    LIKE2BUILD
    Explorer
    Oct 05, 2016
    Perrysburg Dodgeboy wrote:
    LIKE2BUILD, why not dump the surge brakes and go with electric over hydraulic.

    That's not a bad option, but I have a lot of other places that money needs to be used right now. We have some big trips planned next year and we're sending our oldest off to college so I have to be a little more thrifty. It's definitely something to consider in the future but my main focus needs to be making it work with minimal expense.

    BTW, I recently switched the pigtail on the boat trailer to a standard 7-way adapter. All of my vehicles have that plug and I got tired of needing to use 7 to 4 adapters. Plus, that got me direct access to the reverse voltage on the center pin of the socket.

    K
  • Perrysburg_Dodg's avatar
    Perrysburg_Dodg
    Explorer
    Oct 05, 2016
    LIKE2BUILD, why not dump the surge brakes and go with electric over hydraulic. I had the hitch coupler replaced and added the HydraStar HBA-10 to my boat trailer. Was the best thing I have ever done, the trailer will actually lock up the tires now if I set the controller above 6. If you have disc brakes you will need the HBA-12 for single axle or HBA-16 for dual axle brakes. The brakes are only applied when you apply the TV brakes.

    Here are a few pics of my trailer during the install, BTW the system uses the standard seven wire RV plug.

    I added a SS mounting bracket to raise the unit up to make sure it doesn't get submerged in water.



    Don
  • LIKE2BUILD's avatar
    LIKE2BUILD
    Explorer
    Oct 04, 2016
    transamz9 wrote:
    Your truck plug has a dedicated ground and that is the bottom left blade when you open the little flap on the truck. I would run a dedicated ground wire to the trailer plug. Everything on my boat trailer has a ground wire that is connected to the plug. If I'm not mistaken, some lockout solenoids only have a power wire and ground through the brake line. You might be able to take a Stainless hose clamp and clamp a wire to the brake line close to the solenoid and tie it in that way.

    Yep, I have a dedicated ground wire in the 7-way harness on the boat that connects the truck plug with the trailer frame for grounding. I'll have to take a another look at the solenoid to see if it has a ground wire, uses the frame for ground, or if it uses the hydraulic line. I'm glad you mentioned that because now I realize I'm not quite sure.

    Kj
  • transamz9's avatar
    transamz9
    Explorer
    Oct 04, 2016
    Your truck plug has a dedicated ground and that is the bottom left blade when you open the little flap on the truck. I would run a dedicated ground wire to the trailer plug. Everything on my boat trailer has a ground wire that is connected to the plug. If I'm not mistaken, some lockout solenoids only have a power wire and ground through the brake line. You might be able to take a Stainless hose clamp and clamp a wire to the brake line close to the solenoid and tie it in that way.
  • LIKE2BUILD's avatar
    LIKE2BUILD
    Explorer
    Oct 04, 2016
    Grit dog wrote:
    Ya, check ground from truck to trailer. Seems like first trip with the boat every year the rev lockout solenoid doesn't want to do it's job. Then when I get home it works! Rust in the trailer hitch tongue maybe?
    Truck should have power there already as you found out.

    I'm banking more on the thick factory coating on the frame. The trailer has a swing away tongue but I have the ground wire secured to the frame behind that.

    I found the marker lights that weren't working had a hole drilled through the frame and it was relying on the threads of the bolt contacting the frame to get ground conductivity. Of course those threads were rusty so I scraped off a small area of the coating where the light body contacted the frame, slathered the fresh frame metal in dielectric grease, then reinstalled the lights. They worked perfectly after that. I'll bet I need to do something similar with the lockout solenoid.

    KJ
  • Grit_dog's avatar
    Grit_dog
    Navigator
    Oct 04, 2016
    Ya, check ground from truck to trailer. Seems like first trip with the boat every year the rev lockout solenoid doesn't want to do it's job. Then when I get home it works! Rust in the trailer hitch tongue maybe?
    Truck should have power there already as you found out.
  • blofgren's avatar
    blofgren
    Explorer
    Oct 04, 2016
    Correct, they are wired from the factory. The reverse lights on my fiver work perfectly with my 2013 Ram 3500.
  • LIKE2BUILD's avatar
    LIKE2BUILD
    Explorer
    Oct 04, 2016
    Funny what a little searching does. According to the Ram Zone Blog the factory 7-way already has the reverse lights wired to the center pin. :S

    I guess I'll have to first confirm that I have +12 volts on that pin when the truck is in reverse. If that's working fine I guess I'll start digging around on the trailer. If the reverse solenoid is not getting power it might be a grounding issue. Ranger puts a thick coating on their trailers, almost like rhino lining. I've had some marker lights that didn't want to work because they lost conductivity with the frame metal due to the coating. That could be the issue if the truck is sending voltage but the solenoid is not engaging.

    I'll post back once I have time for a little testing.

    KJ

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