Cobra tail light swap help

Discussion in 'SVT Tech Forum' started by mgriffins98, Feb 7, 2010.


  1. mgriffins98

    mgriffins98 New Member

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    Ok so I have a 2001 Cobra that I swapped out my ambers for a set of the all red tails. I wanted to install a sequential kit and have them tinted which I did. The swap went ok. They light up, brake and the sequential kit works. I used the GT harness that I got with the lights also FYI. Now the problem that im having is when I use the blinkers, all the rear lights flash. It looks like my hazards are on when you use the blinkers. Now I know that the cobras have a separate turn signal feed cause of the amber signals. Im guessing I need to combine the turn signal wire with the brake feed wire? I have searched endless for info and have yet to find someone who has done this. Alot of people have done the opposite by putting cobra tails on there GT's, etc. Does anyone know what color my turn signal wire is or have any ideas at all. PLEASE I need this figured out ASAP.
     
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  2. COBRA90GT

    COBRA90GT Mod Dude

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    FWIW - Deleted your other thread in "SVT Talk" (please, no duplicate threads).

    Thanks -staff

    BTW - Can't help you with the wiring part, but if you have a test-light maybe you can start checking for which wires get 12V + for the signal activation ? :shrug:
     
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  3. mgriffins98

    mgriffins98 New Member

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    That is something I need to do.
     
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  4. wmburns

    wmburns SN Certified Technician

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    Cobra brake light wiring changes (fix)

    For the Cobra, the left/right brake lights are wired together. Therefore, it makes sense that both sides turn on at the same time (circuit feed back).

    To fix, combine the brake circuit and the turn circuit with each side. HOWEVER, the fix is to break the DG circuit back to the multi-function switch.

    Left side: combine LG/OG with the DG towards the lights. Break DG back to multi-function switch.

    Right side: combine OG/LB with the DG towards the lights. Break the DG back to the multi-function switch.

    If this doesn't make sense, suggest getting a copy of the wiring diagrams for yourself. It will be obvious why it is working the way that it is. This changes makes the Cobra look like the GT (note, the wiring harness are different).

    Note, the alldatadiy diagrams are much too large to post.
     
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  5. mgriffins98

    mgriffins98 New Member

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    A little confusing. I have this diagram. Is it similar?
    [​IMG]
     
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  6. wmburns

    wmburns SN Certified Technician

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    Look at the "E" and "F" arrow. Note they are connected together at splice S323. This is the source of the circuit feedback.

    On diagram 90-4, Arrow "E" and "F" is what has to be broken between the distribution and the lights. Then bridge the DG wire (circuit 569) to its corresponding turn lights and it should work just like the GT.

    One possible problem may be the increase in load. 3 lights instead of 2. The sequential kit may reduce the load so that is not a problem.

    Good luck.
     
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  7. mgriffins98

    mgriffins98 New Member

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    OK wow thats alot to take in. Thanks for the info. So do you think that this would be easier than putting in a GT harness. The one that plugs in above the drivers side wheel well? Also I have a few dumb questions. 1. What is the mulit-function switch and where is it located?
    2. Are these what the colors are: LG= light green, OG= orange, DG= dark green, LB= light blue
     
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  8. wmburns

    wmburns SN Certified Technician

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    The multifunction switch is in the steering column.

    I really don't know how much work it would be to replace a wiring harness that runs the length of the car. My guess is a lot.

    The colors mentioned are correct.

    If you are concerned about "hacking up" a factory harness, do the alternations at the connectors in the trunk. From the car side, release the DG pin from the connector and pull it back. Tape it to prevent shorts.

    On the other side of the harness (towards the lights), jump the stop and turn lights together. Because the DG wire has been removed, the source of the feed back is gone.

    In this way, the car's wiring harness could be easily restored.
     
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  9. mgriffins98

    mgriffins98 New Member

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    OK I took a pic of the harness next to my steering column a few days ago. Is this the multi-function switch? If so I do unplug the DG wire already just to see what happens but it did nothing. So I need to leave that DG wire out and connect the other 2 together? What you mean by "jump and stop". Just tape connections together?

    [​IMG]
     
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  10. wmburns

    wmburns SN Certified Technician

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    Look at diagram 90-1. If the DG wire is removed between splice S323 and the multi-function switch (like you have done), then the entire brake light system quits working. Put that DG wire back.

    The re-wire work needs to be done in the TRUNK on connectors C460 & C461.

    On connector C460 (left) car side, remove the DG wire from the connector
    On connector C460 (left) light side, splice together the LG/OG - DG.
    On connector C461 (right) car side, remove the DG wire from the connector
    On connector C461 (right) light side, splice together the OG/LB - DG.

    Splice together means to combine together electrically. How you do it exactly depends on your preference (there are several methods depending upon your skill level and the goals).

    If you still do not understand how to do this, then consider replacing the entire harness.
     
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  11. mgriffins98

    mgriffins98 New Member

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    That DG wire has been unplug for a week now and I drive it everyday. The brakes work fine as well as the seq. kit.

    I will let you know what happens...probarly wont be for a few days until I can do it
     
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  12. mgriffins98

    mgriffins98 New Member

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  13. wmburns

    wmburns SN Certified Technician

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    The brakes work because they are being powered by the DG wire starting from splice S323. Look at diagram 90-1. The brakes are being powered via arrows "E" and "F".

    The DG wire you removed is down stream of splice S323 in connector C288/C241 (multi-function switch).

    Look at diagram 90-1. The DG circuit needs to be interrupted before arrows "E" and "F". The intent is to power the left/right lights from arrows "C" and "D" ONLY.

    This thread was stated because the turn signals flash on both sides. Obviously the brake lights work. Aren't we trying to make the brake and turn signals work?

    I get the feeling that you do not understand the reason for the changes or why the turn signal/brake light circuit is feeding back via splice S323.

    Once the changes are made, you will still have to reslove the integration with the sequential tail light kit. Depending on how it works and how you wire it, it could cause both tail lights to sequence when the brakes are activated. If that's OK with you, then call it a day. Otherwise, the signal from the DG wire will have to remain separate from the turn signal and the operation resolved in the programming/wiring of the sequential turn light kit.
     
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  14. mgriffins98

    mgriffins98 New Member

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    Alright I kinda get what your saying. It pretty much starts under the dash and continues through another connector thats in the trunk. It will still get power until I do it to the connections in the trunk (remove DG wire). Is that the harness on the drivers side around the wheel well? Sorry about not getting it, reading and understanding wiring diagrams is not my thing. I know its like your repeating yourself but when you say the left and right side of the car, are there 2 harnesses in the trunk or are you referring to the wiring for each side of the tail lights. Again sorry for my confusion here. I really appreciate your help...:hail2:
     
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  15. wmburns

    wmburns SN Certified Technician

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    When I say Left/Right, I am referring to the Left tail light assembly or the Right tail light assembly.

    On the diagrams, every connector and splice is numbered. I used Ford's numbering system to be as clear as possible.

    When I say to make the changes in the trunk, I mean to open the trunk and look in the trunk for the tail light assembly connectors to the main car body harness (in the trunk).
     
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  16. mgriffins98

    mgriffins98 New Member

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    OK great. Hopefully tomorrow I can give it a shot.
     
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  17. Kid Capri

    Kid Capri Founding Member

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    I know that this is a very old post, but I want to add some information to help out anyone that wants to add gt tailights to a cobra harness. Ill make it short, simple and easy.
    First off, get a regular gt tailight bulb harnesses and replace your cobra taillight harness with them. Now match up the wires from the gt bulb harness to your existing body harness by either splicing or using a new conector, doesnt matter how you do it just match them up. Light green with orange stipe for the left side and orange with light blue stripe for the right, brown with brown black to black, easy. Now on your body harness you will have a dark green wire left, you will not be using this wire anymore, so tape it off or cut it, it doesnt matter. The leftover dark green wire actually is spliced from the 3rd brake light for use on the cobra only.
    At this point your left and right blinkers, hazards, etc. will work with the exception of your brake lights. Now lets get the brake lights working by pulling off the drivers side kick panel. Under the panel you will see 3 plugs just under the hood cable/handle. You will be working on the two square plugs, c331 and c332.
    You will not have any brake lights at this time and this is due to the cobra harness using a splice from the 3rd brake light (darkgreen wire) to power them. Youll need to add a jumper from pin number 15 on c331to pin number 12 on c332. Both pin number 15 from c331 and pin number 12 from 332 are dark green, exact same color as the left over wire from your body harness in the trunk (its actually the same wire, it is labled as wire number 569). This jumper will replace the function of the original splice in the trunk from the 3rd brake light that you are no longer using. When your finished your brake lights and blinkers will work as they should.
     
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  18. xsellr8

    xsellr8 New Member

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    Did you run into problems when trying the sequential part, or from the harness. Can you plug a GT harness into a Cobra and have it work fine?
     
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  19. xsellr8

    xsellr8 New Member

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    I just read the post above mine. Apparently a GT harness requires work
     
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