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Trailer wiring question...need ASAP.

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  • Trailer wiring question...need ASAP.

    Hey guys-

    I recently bought a used TAHOE with the tow package. There was not a wiring harness on the truck so I went down to UHAUL and told them my make, model, year and they sold me a 4 way flat plug (with the indicator lights to let you know everything is connected okay). So,I wired it to the rear of the truck and everything seems to work okay. Here is the problem.....when i went to connect it to one of the boat trailers at work...the trailer has a 5 way flat plug and my plug on the truck is a 4 way flat. UHAUL says they dont make a 5 way flat plug. I am assuming that the fifth plug on the trailer is for the reverse lock-out actuator.

    Here is my question....I want to create a seperate wire to connect the reverse lockout actuator on the trailer to the wiring harness on the truck. What wire on the wiring harness do I connect it to? The green, yellow, white and brown wires have all already been connected to the 4way flat plug.

    Any advice would be most helpful.


  • #2

    Typically the 5th wire is for an auxillary power source to supply what ever one wishes to supply with it. (Most I've had experience with, were used to provide power to a battery to keep it charged)...

    Hope this helps... Good Luck
    Working for a livin\' is HIGHLY Over-Rated...[][br]


    • #3
      Old Jeeper, thanks.

      I was right. The 5th wire (blue) powers the reverse lock-out solenoid on this trailer.


      • #4
        gReen= Right [it has a R in it]

        yeLLow= Left [it has a L in it]

        brown is alway's the running lights

        white is the ground

        And like you said Blue is the revurse back up.

        It can be tied into the back up light's on the truck.

        I hope they installed one of the plug & play wireing harness in your truck and didn't cut and scotchlock your factory harness.[xx(]

        You can buy the plug & play harness's at any Good auto parts store.

        I know Pep Boy's has some of them here, but NAPA should be able to set you up.

        If they cut into your factory harness, then you got [email protected]#ked. That is typical of U-Haul.


        • #5
          Blue wire is connected the the reverse lights, so when you back up with surge brakes you dont lock them up. I remember thinking I wouldnt need it.. Wondered why the trailer had bald tires after backing it up a few times. Thats when I was a young lad though, now the HD is prewired. oh so lovely!!
          John S.[br]Lutz, FL aka Tampa[br]Currently transplanted to Tallahassee


          • #6
            All the Ford truck's are since the early '90's.

            Ford decided to just install one wiring harness in all the truck's.

            Depending what option's the truck had they just removed the fuse.

            My '94 F-150 has a electric brake actuater in it. I had it installed. I use to tow a lowboy trailer with my tractor on it.

            The tied the wires to the actuater and installed a fuse. Done!

            The truck has a factory 7pin connector out back.

            Ford also has a box under the hood that has a bunch of relay's in it. In that box it has a 15amp fuse for Right turn/brake, another 15amp fusefor Left turn/brake and a 25 amp fuse for running light's. these are all strictly dedicated for a trailer.


            • #7
              Yeah, my mishaps were with a rented 4 runner in Tennessee. By far the worst towing vehicle I have ever used. I was only towing my John Deere gator on a 16' trailer. It couldnt even get up the hill with out me outside paddling. Yeah, now I have my Teckonsha Prodigy brake controller and I love it. The 2500Hd has the harness and everything just plug it in. Nothing to fool with.
              John S.[br]Lutz, FL aka Tampa[br]Currently transplanted to Tallahassee


              • #8

                Originally posted by Ed Mancini

                Hey guys-

                I recently bought a used TAHOE with the tow package.....

                What year Tahoe? -Pat.
                18ft MonArk tri-hull: 140HP Mercruiser Alpha One - still in be continued[br](I know it\'s not a Mako, but hey, its mine!)[br] Time\'s fun when you\'re having flies![br]president/hostmaster:[br]P.Ring Technologies[br]Cornerstone IT, LLC[br]LOUISIANA WEB HOST, LLC.[br]CompTIA Certified Professional A+/Network+ // Microsoft Registered Partner


                • #9
                  Hey guys-

                  Thanks for the info. I scrapped the UHAUL kit with the b.s. crimps on it and picked up a Hoppy Plug-in system at Autozone that plugs directly into the wiring harness. They only had a 4 way flat system so I still need to add the 5th wire for the reverse lock-up solenoid but the Hoppy system was so much better and easier than the UHAUL P.O.S.

                  The Tahoe is a 1995- when I bought it in May it had only 16,500 original miles. Some old guy owned it and only drove around town with it and then he passed away. His wife then traded it in for an Equinox or something similar. Car is brand new inside and out....



                  • #10
                    Blue one on my ford 350

                    Oakley, California