This may have been posted somewhere else, so I apologize if this a repeat.
I have been working with Steve from Tousley Ford on a hatchback wiring harness for my 03 SVT. The harness for the 2003 SVT shows as discontinued. However, the harness for the 2004 is still available. Not knowing whether it was the same or not, I took a chance and ordered it. Steve priced it to me for $52 +shipping. I have had the harness for a month, too hot here in Kansas. So today I decided to take a look at it.
The first mistake I made, was thinking that the harness connected somewhere up in the headliner. It does not. It connects behind the sub woofer in the hatch. Unfortunately I had taken the entire left side loose before figuring this out Those crappy grab handles are a PIA.
The hatchback harness is the grey one.
Here is a picture of my old harness still in the car.
I do a lot of repairs well, but fixing broken wires in a confined space is not one of them.
This job took some time to get the harness out.
Remove the plastic trim pieces in the hatchback.
Remove the push rivets (2) holding the headliner up in the rear of the car.
Remove the trim piece in the driver side rear above the small window behind the door.
Remove the cover piece for the sub woofer.
Remove the sub woofer, or at least move it out of the way.
Remove the metal bracket that the sub woofer bolts to.
Take screws out of driver side hatch parcel tray holder. (Black plastic piece that the parcel tray attaches to)
Start removing the harness at the farthest connections.
License plate lights
windshield wiper motor
white connector, not sure what it does, maybe the hatch solenoid
Rear window defrost grid
From there start pulling harness from the mounting points in the hatch. I used a needle nose pliers and a flat blade screwdriver to get any pieces left behind.
Remove high mount stop light. I found it easier to remove wiper fluid hose by using a flat blade screwdriver and back it off of the assembly while still mounted. There is an access point with the hatch up to get to it.
Disconnect the wiring harness from the high mount stop light.
If not done already, use a flat blade screwdriver and work the rubber grommets out of the hatch side and the car side of the harness. Use the new harness for reference on where to insert the screwdriver to dislodge them.
Pull harness most of the way out of the car.
With the headliner dropped a little on the rear driver side, you can remove the wiper fluid hose at a connection point by the small window.
The entire harness should pull out now.
The new harness has two differences that I can see.
1) there isn't a ground connection wire in this harness. The 03 harness had one that connected to the same ground point has the wiper motor.
2) the wiper fluid hose is about 12 inches longer than the 03 harness. I just cut to fit. Make sure to orientate the little connector the same as the original. There is a check valve in the plastic piece and if it is going the wrong way, you will not have fluid to the rear wiper.
Those are the only differences I could see.
I installed by doing the reverse of above.
I did not snap the grommets back into the car and hatch until I was sure everything was where it needed to be.
Take care as to not twist the harness when routing it back into the hatch, otherwise you will kink the rubber protection piece between the grommets.
I also tested everything before I snapped it all back together. To my initial frustration, the license plate lights didn't work. I then discovered a blown fuse. I imagine it had been that way for awhile. I quick trip to O'reilly's and it was in working order.
high mount stop light
windshield wiper fluid
windshield wiper motor
I hope this is helpful. Have a great day