2007 Expedition trailer wiring

[chevy24d]

Originally posted by chuck s
If you have the towing package the wire is already there.

The center pole of the 7-pole connector on the rear bumper is backup lights -- technically that pole is "undefined" or "auxillary" but Ford connects it to the backup light circuit. Was like this on my Explorer too....
-- Chuck

I do not have the towing package but will be adding the larger tranny cooler and larger rad. soon.

So does this mean that the wire for the back-up lights is still accessible in the rear bumper or were you only referring to vehicles with the trailer package?

Thanks again for your help!

Mark

ps - did'nt mean to hijack JD but it seams we are in the same boat...

 

[bobthegod]

This from another Expi owner and an RV'er. Forget the backup lights and battery charger line. Use the money to purchase a nice little Honda generator.....this will power all your lights AND charge your battery(ies if you have two). The new generators (2000 watts) are VERY quiet and efficient. If your batteries run down you'll need to recharge them somehow and hooking up the car everytime gets OLD fast. Onan makes a nice add on generator thats called a JUICEBOX that is mounted to the rear of trailer......goes on and off easily so you can use it at home too. But any small generator can be mounted to you rear bumper (of the trailer) and you can run it while in motion also...to charge batteries run a fridge while traveling etc. Stick with the Prodigy brake controller also it's the best one going. I installed one on an exploder and it works like a charm......very smooth and easy to program on the fly. I wouldn't worry alot about trans coolers as you didn't say how heavy the trailer is, tell us more about it and where you'll be towing....Hills or flats. I also suggest looking at your GCVW Gross Combined Vehicle Weight listed in your owners manual. DO NOT go over the limit....voids warranty. You should be able to handle a 5000 lb trailer easily. For more tow rating info go Motorhome.com or trailerlife.com as they have a lot of tow ratings for new SUV's.

 

[chuck s]

To my knowledge neither the trailer battery charge (or Aux) wire nor backup light wire is at the rear bumper unless you have the HD Towing package.

But they're two wires easily added and one is really there anyway with the backup lights on the vehicle.

Trailer battery charge is no more than a trickle charge.

-- Chuck

 

[tk1971]

OK. I'm getting ready to do this, so with everyone's help here (with drawings, pictures, etc), this is what I found with my multimeter and electronic wire tracer:
1) Empty battery charge fuse is live
2) Empty fuse has a connection to the fused output
3) Empty fuse has an ignition 12V and ground
4) The remaining switched relay output goes to the Orange (10ga?) wire to the harness connector inside the engine compartment on the driver's side near the firewall.
5) The other side of the connector does not have a pin and corresponding orange 10ga wire going to the back of the vehicle.

So, with a 30amp fuse and a Radio Shack 275-226 relay (with the tab sawed off), I can get a fused/switched 30amp 12V supply to the harness near the firewall. All I gotta do next is cut the orange wire off the harness and buy some 10ga stranded exterior rated wiring (Underground rated romex?) and put it in it's own wiring loom, then zip tie it to the existing wiring loom going to the back of the vehicle. Tap the reverse light for the backup, and then I'm all set. I think I'll get one of these as well from etrailer: Adapter 4 Pole to 7 Pole & 4 Pole, OEM Style

tk

 

[chevy24d]

Don't forget to take pics for us...

 

[AvroAero]

Good luck!

 

[tk1971]

OK, I got as far as putting together the wiring before it started to get dark and rain.

Here is how the harness looks like (next to the maser cyclinder):

The harness is disconnected and the two wires needed have been cut (as seen in the picture).

Here is female end of the harness. The 12V 30A connection is shown:

Here is the Reverse connection:

So far I soldered the 10ga and 14ga wires to the 12v/30a and the Reverse/15a (connected to fuse #63) wires that were cut off of the harness. I put 2 flexible wiring looms on the total length of the wires and routed the wiring to the back of the vehicle following the original loom for the original hitch wiring. I just zip-tied the loom to the other loom at all the anchoring places. The original loom is pretty well sealed up, but I didn't feel like wrapping 8 rolls of electrcal tape around this loom, but I think it should be fine.

I got the wiring from Home Depot. 10ga and 14ga stranded service entrance wiring ($16).

Got me a Hoppy 47185 4-pole flat to 7-pole + 4-pole adapter, so it's as plug n' play as it can be. I now have an idea how to secure the new tow adapter (which has both 4-pole and 7-pole) to the hitch. The existing flat-4 connector is held in place by a metal ear welded onto the hitch. This ear has just enough metal for me to drill 2 holes in it. I can then use an angle to secure the Hoppy connector.

I'll have pictures of the final part when I get to it.

tk

 

[chuck s]

Are you running the trailer battery tow and backup lights thru relays?

Without a battery charge relay you can drain your starting battery when stopped if the trailer is using a lot of 12v amps.

The photos I posted near the top of the thread show where the battery charge relay and fuse go.

The diagrams show the box lay out in schmatic form.

-- Chuck

 

[tk1971]

Chuck,

It was your photos and correspondng diagrams that inspired me to check the stock relay/fuse box.

I will be using the stock battery charge relay and fuse. The wiring and the fuse box is the same at this point. The only differnt wiring is the harness connecting to the fuse box harness going to the back of the vehicle, which is missing the pins and corresponding wiring, so I had to run new wirng for the charge and backup.

I'll be using a Radio Shack 275-226 relay which fits the stock relay slot. I'm also tapping the 12V once the 7-pin connector is installed for backup lights.

tk

Thanks..

tk

 

[chuck s]

Looking good to me!

-- Chuck