2004 Expedition - help me identify this rusted box driver side rear corner

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

whtbronco

Full Access Members
Joined
Nov 13, 2021
Posts
570
Reaction score
248
Location
Winchester, VA
Seriously what is this box for in the driver side rear corner just below the tail light? I can't figure out what's in it. Can't get to it from the tail light recess. Ford generally doesn't produce something like this for nothing and it's not the same on the passenger side.

There is a formed sheet of like 1/8-3/16" black plastic visible in the hole and some expanding foam that appears to have been used as an adhesive for the plastic to metal.

While doing the fuel pump last weekend I realized this rust was back and worse. So I started investigating and found it was pretty rotten. I removed all I could tear off and drenched it with acid, let it dry and covered it with 2 layers of foil tape as a temp repair to hopefully keep water out.

I was planning to cut it out and replace it this coming weekend, but with 8-12" of snow now expected I'm not gonna want to be outside working on the truck. Not to mention this is the first real snow since my son started driving so it's time to teach him how to drive in snow. There's nothing quite like a RWD Ranger for learning to drive in the snow :) .
 

Attachments

  • Exp Rust 1.jpg
    Exp Rust 1.jpg
    191.4 KB · Views: 44
  • Exp Rust 2.jpg
    Exp Rust 2.jpg
    196.5 KB · Views: 43
  • Exp Temp Repair.jpg
    Exp Temp Repair.jpg
    174.7 KB · Views: 43

Hamfisted

Full Access Members
Joined
Nov 20, 2012
Posts
2,630
Reaction score
1,504
Location
Ft Lauderdale
Do you have any dealer installed options? Power running boards? Suspension ? Towing options ?
Pull the plastic box out and see what it is.


Expy Left Rear Corner Underside ....
Expy Rear Corner.jpg




.
 
Last edited:
OP
OP
whtbronco

whtbronco

Full Access Members
Joined
Nov 13, 2021
Posts
570
Reaction score
248
Location
Winchester, VA
Hmm, well that is certainly not what I expected to see, :) . I would agree that is likely from someone else's handy work, but I bought this thing with 13 miles on it and have more or less let no one touch it since. It's also spot welded and painted just like everything else under there. I dunno. Thanks for the reply though, at the very least I feel a little less foolish for not knowing what it is.

I guess I'll have to get my wife to take some more pics as I open it up and repair it to try and figure just what the heck it is.
 
OP
OP
whtbronco

whtbronco

Full Access Members
Joined
Nov 13, 2021
Posts
570
Reaction score
248
Location
Winchester, VA
Do you have any dealer installed options? Power running boards? Suspension ? Towing options ?
Pull the plastic box out and see what it is.
There were no dealer installed options, I don't think. I avoid dealer installed options, if it's not factory installed I'd rather install it myself. As soon as I have time to repair this I'll post some pics and description of what I find. It's certainly intriguing.

I feel like that orange expanding foam type material contributed to the rust.
 

mehno

New Member
Joined
Dec 17, 2023
Posts
1
Reaction score
0
Location
TN
I believe that is a storage box but it also contains a reset button. I was told when I bought my expedition that if you ever get rear-ended from behind and the car doesn't start then you need to hit that button to reset the fuel because there's some sort of switch that turns off the fuel tank I believe.


Seriously what is this box for in the driver side rear corner just below the tail light? I can't figure out what's in it. Can't get to it from the tail light recess. Ford generally doesn't produce something like this for nothing and it's not the same on the passenger side.

There is a formed sheet of like 1/8-3/16" black plastic visible in the hole and some expanding foam that appears to have been used as an adhesive for the plastic to metal.

While doing the fuel pump last weekend I realized this rust was back and worse. So I started investigating and found it was pretty rotten. I removed all I could tear off and drenched it with acid, let it dry and covered it with 2 layers of foil tape as a temp repair to hopefully keep water out.

I was planning to cut it out and replace it this coming weekend, but with 8-12" of snow now expected I'm not gonna want to be outside working on the truck. Not to mention this is the first real snow since my son started driving so it's time to teach him how to drive in snow. There's nothing quite like a RWD Ranger for learning to drive in the snow :) .
 

kep5niner

Full Access Members
Joined
May 6, 2023
Posts
135
Reaction score
108
Location
MO
I believe that is a storage box but it also contains a reset button. I was told when I bought my expedition that if you ever get rear-ended from behind and the car doesn't start then you need to hit that button to reset the fuel because there's some sort of switch that turns off the fuel tank I believe.
IMG_0775.png
 
OP
OP
whtbronco

whtbronco

Full Access Members
Joined
Nov 13, 2021
Posts
570
Reaction score
248
Location
Winchester, VA
Well yeah the inertia fuel cut off and the air suspension switches are in that area. I am familiar with both, but they are above the floor pan, though directly over this thing. This box appears to be entirely under the floor pan and is not sealed so if it is associated with the switches I'd expect to have some dust in there. At some point over the next few weeks I'll cut it out and we'll know. I'm certainly looking forward to welding above me, yikes.

After studying the pic posted by Hamfisted mine looks the same, well except the hole rusted in it, haha.
 

JamaicaJoe

Full Access Members
Joined
Dec 20, 2020
Posts
690
Reaction score
272
Location
Oviedo FL
In the earlier generation, the evaporative canister is located in that corner. Are their hoses to the fuel tank and forward to engine?
 

JamaicaJoe

Full Access Members
Joined
Dec 20, 2020
Posts
690
Reaction score
272
Location
Oviedo FL
I almost bought a VW Jetta until I noticed someone had cut a rectangle from floor out of the trunk and then welded back in. Underneath it appeared there once had been a boxed in area. You have to wonder why.
 
Top