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Thread: Brake light wiring question

  1. #1
    Join Date
    Feb 2005
    Location
    Alpine, UT
    Posts
    96

    Brake light wiring question

    Hi folks-

    Thanks to Alan, I have a call in to the manufacturer of the harnesses for the Unique cobras, but thought I'd check in here in case anyone's been through their wiring harness and can beat them to the punch.

    Here's my setup: I'm using the turn signal stalk from the kit, but am wiring in a Ron Francis harness (there were a few things I wanted to do differently, so I went custom.) I have everything wired up and working except for the brake lights, and I'm trying to figure out where the "cold" side of the switch goes. I have a +12v hot lead going from my fuse panel down to the switch, and I have a wire coming from the cold side of the switch back, ready to be terminated "somewhere"

    I suspect, since there's only one bulb per side in the rear, that the brake lights are on the bright filament in those bulbs just like the turn signal. If I splice the wire from the brake switch into the turn signal wires the brake lights will cancel out the turn signal, and I won't signal as long as the brake lights are on.

    From what I understand, many turn signal switches have a provision for this, whereby when the turn signal switch is activated, it breaks the circuit to the brake light, only providing current from the flasher to the tail light, to ground.

    So I'm wondering if there's a provision in the turn signal switch shipped with the kit that opens the brake light circuit when the turn signal is activated, breaking the brake light circuit so that the turn signal will flash when the brakes are applied.

    If the turn signal switch doesn't have that provision, is there another way of achieving this?

    Thanks!
    Chris
    Last edited by cwareham; February 18th, 2008 at 12:46 PM.
    Big engines in little cars.

    289 FIA, 347, Tremec 3550, Edelbrock performer RPM heads, air gap intake, hydraulic roller 227 intake 234 exhaust at .050. Ford Guardsman Blue paint.

  2. #2
    Join Date
    Jan 2004
    Location
    Houston, Texas
    Posts
    137
    Chris,

    This is a response to your question from Bobby Hughes, EE, that has done the wiring on my 289 Unique Roadster. Bobby has done the wiring on all of my race cars for the past 15 years and I've never had a problem with anything he has done.


    I suspect, since there's only one bulb per side in the rear, that the
    brake lights are on the bright filament in those bulbs just like the
    turn signal. If I splice the wire from the brake switch into the turn
    signal wires the brake lights will cancel out the turn signal, and I
    won't signal as long as the brake lights are on.
    correct

    From what I understand, many turn signal switches have a provision
    for this, whereby when the turn signal switch is activated, it breaks
    the circuit to the brake light, only providing current from the
    flasher to the tail light, to ground.
    correct again. The Unique one does not have this.

    So I'm wondering if there's a provision in the turn signal switch
    shipped with the kit that opens the brake light circuit when the turn
    signal is activated, breaking the brake light circuit so that the
    turn signal will flash when the brakes are applied.

    If the turn signal switch doesn't have that provision, is there
    another way of achieving this?
    Terry's car came with an adapter wired in which is sold at trailering places to adapt a car with separate brake and turn signals to a trailer with combined brake and turn lights. Apparently the turn signal connections from the switch are connected to the turn signal inputs, the brake switch is connected to the brake light inputs, and the left and right outlets are then connected to the bright filaments of the bulbs. The adapter is the magic answer, unfortunately we just put the dash back in this afternoon and it is hidden so we can't see a name or part number. But any auto supply or trailering supply place should know what you want.

    --
    Robert W. Hughes (Bob)
    Hopefully this will be of some help to you!

    Regards,
    Terry
    Viking Blue 289 Competition Model
    #9527
    Southern Automotive 351W
    Tremec TKO 600 5 speed
    3:42 Limited Slip
    3-piece Compomotive 17" Pin Drives

  3. #3
    Join Date
    Feb 2005
    Location
    Alpine, UT
    Posts
    96
    Perfect!

    Thanks Terry.

    All the best,
    Chris
    Big engines in little cars.

    289 FIA, 347, Tremec 3550, Edelbrock performer RPM heads, air gap intake, hydraulic roller 227 intake 234 exhaust at .050. Ford Guardsman Blue paint.

  4. #4
    Join Date
    Jan 2004
    Location
    Houston, Texas
    Posts
    137
    Chris,

    I'm glad it was of some help for you! Keep me posted on how your car is coming along, OK?

    I'm going to post some new ones on my 289 roadster when I can ever get them downloaded and put on my server so I can post them. We finished the wiring last night, radiator hoses & plumbing and I mounted the oil cooler and ran all the lines for it. Now we just have 1 brake line to finish, the hydraulic clutch line and fuel line to the fuel pump and we are finished with all the mechanical things ( I hope). Next is the interior and then it is ready to "fire off"!

    Oops...forgot the emergency brake handle and cables...then we are through with the mechanical things for a while.

    Regards,
    Terry
    Viking Blue 289 Competition Model
    #9527
    Southern Automotive 351W
    Tremec TKO 600 5 speed
    3:42 Limited Slip
    3-piece Compomotive 17" Pin Drives

  5. #5
    Join Date
    Feb 2005
    Location
    Alpine, UT
    Posts
    96
    Looking forward to those pics.....it'll be a while before we go to paint (planning to drive in gelcoat this year) but I'm planning on going light blue and would love to see what yours looks like in Viking blue.

    Would also be cool to connect at TWS. I haven't been solo'd by PCA there (not sure who else runs at TWS) so I don't know how I'd get the cobra on the track. I have an LS1-powered RX7 that I ran there with some buddies a few months ago and had an absolute hootenanny.

    All the best,
    Chris
    Big engines in little cars.

    289 FIA, 347, Tremec 3550, Edelbrock performer RPM heads, air gap intake, hydraulic roller 227 intake 234 exhaust at .050. Ford Guardsman Blue paint.

  6. #6
    Join Date
    Jan 2004
    Location
    Houston, Texas
    Posts
    137
    Chris,

    We are going up to TWS this weekend to run a DE event in the 1965 Mini Cooper S that I am part owner in. These DE (Drivers Edge) events give you all the track time that you could possibly want. There are different classifications for drivers from pure novice to licensed competition drivers. My partner runs in the Blue or Yellow Group...the intermediate group with a lot of track time. I run usually run in the Blue or Red group as I've been an SCCA Certified Instructor for years. The only reason I haven't been running only in the red group is that the Mini just isn't fast enough to keep up with the Porsche's, Vetts and etc. Now that I have the FIA Cobra I'm sure that I will only be allowed to run with the other instructors in the Red group.

    Attached are a couple of shots of the car.

    The dash with the MSD location:



    This one shows the fan, Moroso water filler and our Black Aeroquip hose and anodized black fittings:



    This one is of the Compomotive Rear 3 piece knock off 17 X 12.5 with BFG 315/35ZR 17" G Force 1 Radials. Puts down a 12.5" foot print per tire.



    As we unloaded it at home!



    And my first full frontal shot



    Hope you like them!
    Terry
    Viking Blue 289 Competition Model
    #9527
    Southern Automotive 351W
    Tremec TKO 600 5 speed
    3:42 Limited Slip
    3-piece Compomotive 17" Pin Drives

  7. #7
    Join Date
    Feb 2005
    Location
    Alpine, UT
    Posts
    96
    Beautiful pics Terry thanks for sharing!

    Re: the DE events at TWS, as a novice can I get a single rollbar car onto the track? I was able to do it at Pocono when we were back in NJ, but it was clear with the PCA at TWS that it would be a no-go. I'm more about big engines in little cars than a road course driver, but the opportunity to get the car out and stretch its legs a bit is fun, and TWS is a great track!

    All the best,
    Chris
    Big engines in little cars.

    289 FIA, 347, Tremec 3550, Edelbrock performer RPM heads, air gap intake, hydraulic roller 227 intake 234 exhaust at .050. Ford Guardsman Blue paint.

  8. #8
    Join Date
    Jan 2004
    Location
    Houston, Texas
    Posts
    137
    Chris,

    Thanks for the nice compliments on the car. It is coming along nicely and I hope to have it finished in time for the Texas Cobra Feast at the end of March in Austin.

    I'm not sure if you can get a single rollbar on the track for the first time I'll ask for you this weekend while there. I can as I am an "approved driver" for these events...something to do with my 30+ years of having an SCCA National Competition License, I think!

    They usually want you to take an instructor with you for the first few times on the track and I don't think they will do that without a full rollbar...but like I said, I'll find out for you this weekend.

    Hope to meet you soon.

    Regards,
    Terry
    Viking Blue 289 Competition Model
    #9527
    Southern Automotive 351W
    Tremec TKO 600 5 speed
    3:42 Limited Slip
    3-piece Compomotive 17" Pin Drives

  9. #9
    Join Date
    Feb 2005
    Location
    Alpine, UT
    Posts
    96
    Terry-

    If you make it up to Austin for the feast end of March, I'll see you there. Good chance I'll be on the road by then, but even if I'm not I'm planning on attending at least one day.

    All the best,
    Chris
    Big engines in little cars.

    289 FIA, 347, Tremec 3550, Edelbrock performer RPM heads, air gap intake, hydraulic roller 227 intake 234 exhaust at .050. Ford Guardsman Blue paint.

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