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Frankly
Explorer
Apr 22, 2017

2006 Expedition W/Tow Pkg But No Charge Wire

I hooked up my new trailer expecting it to charge the battery while I drove. However, after some exploratory surgery I found that it had no charge wire hooked up. It did have the brake controller wired for the brakes. I finally discovered that my vehicle tow package only had the 4 pin plug installed. It apparently also had a brake wire in the bundle, as well, although I am guessing it was not hooked up. The 7 pin plug was added by a jack leg who was either too lazy or not motivated to install the charge wire. I finally figured out that the factory charge wiring stopped just under the drivers door and so I had to run the charge wire back to the plug from there. I had to add a relay and a fuse in the fuse box inside the vehicle. Not sure if anyone has run into this. The hard part was figuring everything out. If I had not had the Ford Service Manuals, I doubt I would have?:thumb:
  • Well just to document the final end of my story here. As stated earlier my Expedition came with the heavy duty towing package with a 4 pin plug minus the 7 pin plug. Of course, I do have a 7 pin plug, but the installation is definitely not factory. It was obvious that the factory 4 pin harness was installed with the blue brake wire taped up inside the loom. The 7 pin harness was spliced into the wiring with crimp connectors without a charge wire.

    Since several respondents have cautioned that I may not have the heavy duty towing package, I have done the following:

    1. I verified I have the 7A095 auxiliary transmission cooler.
    2. I verified I have the 3D746 power steering cooler.
    3. I verified I have the 8005 Radiator, which is the only one available for 06.
    4. I have added a Scan gauge and programmed it to monitor the tranny temperature.
    5. I have added a 12 gauge charge line by tapping into the 12 gauge orange wire under the drivers door attached to the frame (yeah I know it should have been 10 gauge).
    6. I have added a 30 amp fuse and relay to the passenger side kick panel fuse box in the trailer charge wire positions.
    7. I need to have the tranny fluid changed - as it is original most likely.

    Once No. 7 is complete and I get some free time from work, I am ready for some heavy duty hauling and camping.
  • Some Fords also have a breaker or fuse for trailer charging. You should check yours.
  • Agree with others. IF it did not come with the 7 pin. It does not have the tow package. Meaning NO trans cooler, or power steering cooler, and so LESS tow capacity.
  • I'm pretty sure my truck was originally a rental. It's hitch is not standard. It had only the 4-way plug. The wiring for the 7-wire was hidden away above the spare tire. I believe I had to plug the new harness into the 4-wire and then splice into a couple of other wires. Two being the brakes and the 12v power. It should already be up there.
  • Ford sold them with 2 tow packages. The light duty package, which included the 4-way plug, and the heavy duty which included the 7 way plug and extra cooling.
  • You do not have the factory tow package. If you did, it would have the 7 pin and 4 pin connection already wired and hooked up.
  • My 2012 F-150 had a bundle in the back driver's side behind the fender well above the spare. There are harnesses you can buy that will plug into that plug and go to the 7 connection rv plug. The blue wire, I believe is the 12v to charge the trailer battery, or it may be the brake. Can't remember. Google it and see what colors are for what. The harness I got I had to splice into the 12v, as per it's instructions.
  • My daughter's 2012 is EXACTLY the same way ! Additionally, you probably do NOT have the heavy duty radiator or the auxiliary transmission cooler. The radiator is a straight drop in. The trans cooler takes some extra hoses, etc.

    What color is the wire ? I assume the wire bundle is under the vehicle not inside, correct ?