Okay, here's my story. I have a 2002 Expedition that did not come with the tow package, so I am going through all the steps to make it tow ready. I installed a Class III hitch. The next thing I did was buy this 7-way harness to replace the 4 pin setup at the rear, you can see it

here . It came with the necessary relays and fuses for the fuse box under the hood on the drivers side.

I have a B&M tranny cooler to install this weekend. There's a chance I guess that I may have a smaller main radiator? Hopefully I'll be okay without having to pony up for the bigger radiator. Here is where I've reached a stumbling point however. Since the Expy did not come with the tow package, there is no convienient brake controller pigtail under the dash. I know that there is the full complement of wires, including the brake wire, that leads back to the 7-way harness that I installed. Where those wires lead to I'm not sure. I'd especially like to know where the blue one is, and where along it's path I'm supposed to connect to it. I guess I could run a new one to the back, but that would be a lot of work that I think I could avoid, and also theres a relay that is labeled "tow electric brakes", and don't I need to keep this relay in the loop? Any help figuring this out would be VERY much appreciated!

 

I can't speak for your specific 2002 Expedition, but for the F150's, even if they did not come with the "tow package" from the factory, they did still have the full trailer wiring setup under the dash for the brake controler and all the wiring to the rear of the truck... It's just 'which' connector you get to the bumper that's the difference..... You automatically get the 4 pin connector because you can tow using the bumber if you wanted too....

All that's needed to be done to get the "tow package" setup is to get the factory 7 pin connector that plugs into the wiring harness where the 4 pin does now. Then just add the two relays for under the hood.

The brake controler connector "should" be under the dash, pretty close to the diagnostic port for the computer.

My relays do nothing for the brake controller. One is for the 12v power that gets sent to the trailer to charge the trailers battery when the truck is running. The relay prevents the trailer from drawing power when you shut off the engine. The other relay is for reverse lights on the trailer, if it has them......

If you have the 5.4, you should already have a factory aux trans cooler..... It'll be a tad bit smaller then the one you get with the package, but it's better then nothing..... If you have the 4.6, you'll probably have to add one. You only get the cooler with the package with the 4.6.... Every automatic transmission will have a cooler integrated in the rad. It'll work ok in normal driving, but will not be enough if you tow anything....

Good luck!

 

I've looked hard for that pigtail. On my f-150 it was right there, hanging beautifully right above the diagnostic port. But my Expy, I just cannot find it. It's driving me nuts because I know those wires running under the frame have to lead and terminate SOMEWHERE. I have the 4.6, so I have no tranny cooler, but I've got one ready to install.

 

I as well have a 2002 expedition: It has the wire harness/connector in the rear, but when i went to install a brake controller, much to my suprise there was no connector. I know by all the research and postings it "should" be right there. Did you find yours? if so how, if not what did you do?
Thanks for any info you can give.