GT / Cobra / V6 Fog Light Re-wire
Convertible Top Harness method.

Written by Mustangworld.

NOTE: Wiring your fog lights to work independently may be illegal in your state. You may also be ticketed when running on the road in this configuration.

An article by Brian Carr was sent in to us over a year and a half ago outlining the fog light switch install using the convertible top harness for power.

There has been some confusion as to actually how this is done. Some folks inquire about "swapping wires" etc. Well for most folks a wire cut will actually be necessary, but this method is still not that hard to do.

To clear up some confusion our first article and other articles may have caused, here is the method step-by-step we'll call the BC (Brian Carr) method, in ode to him being the first to post a fog light re-wire article on the web a while ago (on our page of course).

This method can be applied to all Mustangs (GT, Cobras, V6 with fog lights, etc.) provided the convertible top harness is available in your stang.


1. Pull up on the rubber feet of the console area of your stang near the cup holder (pre 98 SN95's). They are slipped on and pop off, no adhesive to worry about. There are 2 located on the left and right sides only in front. Once these two screws are removed, you can pop out the holder area. Unscrew 2 screws
2. Hidden and clipped to a plastic holder you will see a harness (the convertible top harness), black in color with purple wires going to it. Un-clip it and get ready to work on it. Careful not to cut your fingers while working in this area. There are a lot of sharp edges in here. NOTE: This harness may not exist in your stang, check and see. IF YOU have a convertible, then it's already being used, but that's ok, continue reading... Find Convertible top harness
3. Pop your fog light switch through the hole. It simply pops out. You can either push from under or pry from the top. Pop switch out
4. Next, if you have a convertible, disconnect the black harness and pull it through with the fog light harness (gray). Here we show the fog light harness with it's red cap removed. Remove the red cap from the convertible top harness also. Pull both harnesses through
5. Look at the two harnesses. We'll be capping off plug "A" and NOT using it anymore (but still use it's connector). We will be using plug "B" on the convertible top harness for power. If you do not have a convertible, you can pull and cut plug "B" (as shown below) if you DO have a convertible, you will need to SPLICE into the power plug "B" provides. Plug "B" is 12vt accessory power (on when key is in full on position). As you can also see, the plugs are of 2 different sizes. NOT the same size. Side by side look
6. A test also shows that the conv. top harness will be giving your fogs slightly more juice. 12.2 vs 11.15 (or so) the fog power source gave. Something to take into account. But it should be ok. Test leads

7. You will need to buy a couple of Butt connectors to make the wire splices. Radio Shack Part #64-3037 $1.49. Also buy 1 wire "cap" as well. All these connections are crimp on. If you do car stereo or alarm installs, you already have a bucket full of these we're sure ;-) Also, MAKE SURE you have a good crimper tool ! The "crimp" is key, a bad crimp will mean possible arching, shorting, etc. A complete kit with an ok crimp tool costs around $12.

Butt connectors
8. Next remove and isolate the purple / orange wire from the conv. top harness. You have to push the connector down from the top then out the bottom. IF YOU HAVE A CONVERTIBLE LEAVE IT IN PLACE ! Convertible owners will simply "splice" into this wire for power. Isolate wire
9. COUPES ONLY ! Cut the end off the purple / orange wire, because you don't have a convertible, you will never need this connection. IF YOU HAVE A CONVERTIBLE DO NOT DO THIS! You WILL cut this wire, but MUCH further down to allow a splice to be made. So for convertible owners, cut this wire about 1.5 inches from the end of conv. top harness. Allow more room if you need to for your convertible install / splice procedure. Cut for Coupes only !
10. Now cut the red / black wire on the Fog Light harness, make sure you cut it down a bit to allow you to splice the wire to the new power source. Cut red / black fog wire
11. Here we installed a red butt connector on the red / black wire on the Fog Light harness. We will now splice it to the purple / orange wire on the convertible top harness. Here, if you have a coupe, you will put ONE wire end into the butt connector. If you have a convertible, you will be splicing "into" the power source, which means you will be putting 2 purple / orange wire ends into the butt connector on one side. Make sure you strip the wire insolation back a bit on each wire for a proper contact. Connect and cap off
12. Here's the finished install. It shows the fog light power spliced into the convertible top harness power AND the remainder of the original fog power wire "capped" off to prevent arching. If you had a convertible, you would see another purple / orange wire going back into the convertible top harness from the right end of the red butt connector in this photo (to keep your top powered!). Finished install

NOTE: For the convertible install you may need to use a larger "blue" butt connector to allow enough room for the "cut" purple / orange wires to be spliced to the fog light harness.

CHECK YOUR CONNECTIONS! "Butt" connectors can slip. Pull each end tightly to make sure the wires are crimped properly. If a wire slips out, you will need to re-crimp a new butt connector in place. For those who don't know, a "butt" connector is a plastic tube (red shown above) with a metal tube inside of it. You put wires into it at both ends, then squash the metal tube to "crimp" the wires together.

ANOTHER NOTE: The convertible top harness may not reach back into the snap holder. You may need to splice in a longer wire for a proper installation. A longer wire may be nedded for proper location for the convertible plug (for convertible owners) also. We just tucked the harness plug far underneath and out of the way, but not back into it's holder.

Now that's you've read the above notes, you can stuff all the wires back in and enjoy "true" independent operation of your fog lights. Remember that your fogs will operate all alone now. So turn them on at twilight or whenever you want. Go for the "daytime running lights" look if you want. But also remember that when you turn on your brights, your fogs will also be on for an "ultra bright" which can be blinding to passing drivers! Your fog lights will turn off when you shut your stang off even if you leave the switch on, so no battery draining worries there.

Using this method is very similar to running a new accessory power lead to the fog lights which we really recommend. The convertible top harness uses a heavy load fuse, enough to carry the load of the fog lights.

This was based on the info in Brian's article located here. We illustrated it to clear up some confusion that we've read about and received via email.

Til next time... see ya on the street!.

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