Brake light mod

[mot250]

Ok, finally got the brake light mod completed. It will take me a few days to get the How-to completed (with pictures) but here are teaser videos of before and after.

In short, to do this you need two new replacement dual filament sockets (Lawrence at WebElectrics can provide them as they seem to be unavailable anywhere else) a relay and various lenghts of wire, connectors and shrinkwrap.

12 volt power to the relay comes from the 12 volt outlet in the center console. The ground is located near the factory ground near the passenger side tail light. The switching on of the modified brake lights comes from the third brake light circuit (tan wire with blue stripe). Then you run wires from the relay to each of the new sockets. You can reuse the stock tail light bulbs because Ford uses the same 4057 dual filament bulb in all three of the tail-light sockets.

It is not a sequential package but I got the inboard lights to light up with the brake lights only. Normally, the inboard lights only light with the parking lights.

Stock tail light work like this...
http://www.youtube.com/watch?v=tQQKtW60QQc

After my mod, they work like this...

http://www.youtube.com/watch?v=BgfNO0dZayc

To get started...Remove interior trunk panels and lift out the trunk mat. If you have a Mach 1000 sub, that will have to come out also but I don't know how that comes out because I do not have one.

There are 4 push pins and two wing nuts holding the rear panel. The push pins need to have the center part pulled out a bit (with your finger nails) then both parts of the pin can be pulled out as a unit. The wing nut may need some assistance by prying the panel out while turning the wing nut.

The side panels are each retained by 2 barbed pins. I’ve found a pair of curved needle nose pliers works well but you may need to begin prying with a screwdriver to get the nose of the pliers in position.

[mot250]

Remove 3 nuts per side to remove the tail-light housings. Note the black flexible sealer under/around each nut. You can save this and re-form it for a new seal by rolling it out and forming a circle. It can be warmed and rolled between your fingers. Or if you have access to black “strip caulk”, you can discard the factory stuff and form fresh rings. The 3.5 inch by ¼ inch strip shown here is enough to seal all 6 nuts. Later when re-installing these nuts with the seals, the material presses out and will form around the outside of the nut as you see here.

[mot250]

Pull the housing away from the rear of the car. Have a towel handy to protect the bumper. Remove all 3 light sockets (and the reverse-light socket) and the harness retaining pin from each tail light housing.

You will remove the inboard tail light socket from the factory harnes by cutting the two black ground wires and the single blue wire with the green stripe.

From the new replacement socket, you will connect the black ground wire to both of the factory black wires. The new socket’s brown with white stripe (minor) wire will connect to the factory blue wire with the green stripe. The new socket’s blue wire with yellow stripe (major wire) will connect to the new wire you will run through the grommet. In my application, I ran a new blue wire to the driver’s side tail light and a yellow wire to the passenger side tail light.

To run the new wire to the new socket’s major wire, use a wire testing probe through the factory grommet. Then use some dielectric grease though the hole and force the new wire through the hole. The grease makes it easier to get the wire through the poked hole.

To make the splices to this part of the harness that is actually outside of the trunk, I used a soldering iron and some electrical solder. Remember to put the short length of heat shrink wrap on the wire before making the connection.

[mot250]

Replace the light sockets into the tail light housing and remember to replace the harness locator pin into the housing as well. Finally, replace the housings into the tail light panel and install the sealer and nuts. Run the nuts in until the sealer squeezes out as seen in a previous picture.

Inside the trunk, I used crimp on connectors and included a flat blade connection (pink connectors in previous pictures) that could be unplugged for complete removal of the harness as the factory harness can be removed.

From the driver’s side, I routed the blue wire though some split loom and inside the rear panel, exiting near the ground at the passenger side tail light.

I routed the blue wire as well as the new black ground wire (for the relay) and the yellow wire though the factory loom back to near the upper rear shock mount. Then I ran all of these plus the new green 12 volt power wire through a new length of split loom to the wheel well toward where the relay will mount.

[mot250]

The source to power the switching of the relay comes from the third brake light. You can access this wire (tan with blue stripe) on the under side of the rear deck. It runs out of the harness that runs to the passenger side rear deck speaker. If you want to see the wire to confirm the color, remove the truck lid latch cover and see the wires running out of the third brake light socket. That cover panel is retained but 2 spring clips, one on each side. It also attaches by the third brake light and needs to be maneuvered over the latching mechanism.

Run the tapped wire (my white wire) around the “T” junction in the factory loom and back into the factory loom under the side of the trunk by the hinge. Continue in the factory loom down toward where the relay will be mounted.

I mounted the relay with a bolt I had lying around from another long forgotten project (yeah, you can call me a pack-rat). But the benefit of this bolt is that it has a large flat side that prevents it from turning. This means I do not need to put a wrench on the bolt head, only the nut side. Mount the relay on the back side of the panel as I did so that the factory carpeted side trunk panel will fit flush when you are all done.

[mot250]

I again used crimp on connectors to attach all of the wires to the relay. Follow the relay’s wiring diagram for all of the blades. I used a 5 blade relay and I have the driver’s side and passenger side new socket on separate wires (solid blue and yellow as described earlier. Of the other 3 relay blades, one is for my green 12 volt power source (console 12 volt outlet), one is for the black ground wire (grounded near the passenger side tail light as shown earlier) and the last is for my white switched source (to the factory third brake light circuit).

Wire gauge I used:
White – 18g – tap to 3rd brake light – switches on the new sockets
Black – 14g – ground for the relay – terminates near passenger side tail light
Green – 16g – 12 v source – from center console power outlet
Yellow – 16g – power to passenger side new socket
Blue – 16g – power to driver side new socket

[mot250]

To route the green power wire to the source at the center console power outlet wiring, you’ll need to remove the rear seat. There are 2 tabs on the front of the seat. See the picture of where the bats are from under the front edge of the seat base. You can run the green wire through the remaining section of the factory loom in the trunk but it terminates just under the rear seat base. Make sure to route the wire under the seat so that it is secured and is not subject to excessive force. It will need to run under the carpet to tap into the power outlet in the center consol. The upper portion of the console will need to be removed and the base will need to be unbolted as well.

[mot250]

Here are the final touches to complete the project:

To remove the center console to tap into the power outlet, first remove the two Philips screw on the hinge end of the console lid. The parking brake handle should be up in order to remove the top section of the console which includes the cup holders. There are two clips toward the front that will pop loose with a little tug.

You will then be able to see the back side of the power outlet and the green wire to tap into. You will still need to remove the base in order to route the wire under the carpet. You’ll want to unplug it before removing the console base. The console is retained by two 10 mm nuts at the back and two 5mm screws in the front. The side panels around the radio will pop out of their clips when you start to remove the base. Set them aside until you reinstall the base later.

Lift the base of the console up, tilting it forward over the parking brake handle (should again be in the up position). You can now lift the carpet enough to get the wire under toward the center of the console. I used a “T”-tap here into the light green wire that runs to the power outlet. I used a tap that accepts a "blade" type connecter so that can be unplugged if necessary.

You can now begin reinstalling the console base and top, then snap the side panels back in place.

[Wolf]

excellent write up. i think ill do this.

nice job bro.

[Ambenz]

Boy, sure looks like a lot of wiring work!