Drag Racing Tech - T-Brake Wring to Horn Button?!?!
07-25-2012, 07:07 PM
Iv got a th400 w a T Brake, im wanting to activate it w a a arming switch and a dead man, would like to use the horn as the dead man switch, question is where is the wire after the clock spring for it under the dash area?! horn is switched on the Ground Side from factory.
07-25-2012, 07:09 PM
not a great ideal ...if the car gets outta shape and you "hit" the button going down track you will engage the brake causing bad things to happen...
07-25-2012, 07:55 PM
its a after market steering wheel w a thumb button, i dont like the idea of haven it on the shifter knob cause of that same reason....cars got a rev manual valve body in it.
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07-25-2012, 08:42 PM
I am confused...
You are using an aftermarket wheel right?
It has an aftermarket push-button correct?
Is it wired so that the push button on the steering wheel goes through the OEM clock spring, or is it one of those "bungy" looking cords direct off the wheel?
Assuming you are using the oem steering wheel wire, through the clock spring this is what I would do:
(note...same would apply if you are using one of those bungy style cords. they still pull ground from the column)
-Find the groud trigger at the column for the horn.
-Cut the wire and have the signal side (horn side) be the input on a 3 position switch (maybe mounted next to the shifter?)
-Have one position of the output go to the horn (so you can retain factory horn function), and have the other output of the switch trigger a relay for your trans brake.
Ideally, you would pull up to the staging lanes, move the 3 position toggle from horn to brake, get up on the two step, and after the launch put the switch back to the horn or neutral (center position), as to not accidentally trigger the trans brake going down the track if you somehow hit the button on the wheel.
Relay wiring for reversing the polarity of the ground trigger from the horn would be as follows:
Pin 86 - ground input from the horn
Pin 85 - Jumped to pin 30
Pin 30 - fused 12v lead
Pin 87 - Output to 12v side of trans brake solenoid
Pin 87a - not used
Hope this makes sense and helps out a little.
07-25-2012, 09:39 PM
Put button on dash, problem solved.
My trans brake also won't engage in any gear but neutral or 1st gear.
07-25-2012, 09:57 PM
^ that too....
That is how my Caprice is setup.
Right next to the cigarette lighter:
07-25-2012, 10:49 PM
Will A Brake in a TH400 w a manual valve body only trigger in 1st or N? This is my first go around w a T-Brake, I personaly dont think Im gonna have time in a high 9 low 10 sec car to try and turn off the arm switch after a launch and still grab 2nd...
07-25-2012, 10:51 PM
real prb is finding the right ground wire to activate off of after the wire goes down the colum Iv looked all over.... supposed to be a black wire and i think iv hit every single one inside the car
07-26-2012, 08:49 AM
Will A Brake in a TH400 w a manual valve body only trigger in 1st or N?
It depends on the valvebody.
07-26-2012, 04:19 PM
mount it somewhere where you have to pull your whole arm/hand back to release ..that motion is quicker than moving just your thumb..go watch bracket or index racers and see where they mount them ...
07-26-2012, 09:03 PM
Put it in or near the dash or down by the ashtray cubby hole.
07-27-2012, 01:38 AM
Right on as of right now I have a switch panel where my heater and ac controls where and thats where the arm and dead man switch is top left right below the cd player