I have a 95 civic ex 5 speed manual. I'm putting in a push button
start, but I'm not sure what wires to tap into. I have a test light and
I'm pretty good with electrical, but does anyone know the exact wire
colors to tap into on the ignition. I have my haynes manual, but I'm
not to good a reading these diagrams. If anyone knows the wires it
would help. I already have to button mounted and I'm going to put an
in-line fuse instead of a relay and if anyone knows the exact wire
colors to tap into. it would help thanks.
I no longer have them memorized, but here is how you figure it out for ANY
Stop using a test light! They are only good for circuits that you know you
can safely work on with a load. This particular project a test light is
fine for, but what about your next project? Probe the wrong wire with a
test light and you fry a circuit. When in doubt, use a multimeter.
Under the dash, high up along the steering column you will find a bundle of
wires on the right side of the column. Heavy wires (for under a dash)
usually 10 or 12ga. Check each one for 12v while the key is in the crank
Other wires in that bundle...
Constant 12v - Always 12v
Accessory - 12v in Acc and RUN position, dead during crank (don't want to
power unnecessary items during crank)
Ignition - 12v in RUN and CRANK position (only power what is needed during
RUN and CRANK)
Avoid any wire or group of wires in a yellow wiring loom. Those are
universally used as an indicator of airbag wiring. Short those out (or
probe them incorrectly) and the airbags will pop.
Two thumbs up to Seth. He's right on the money.
If anybody wants a quick snapshot on what the ignition switch wires do, see
the diagrams on this Main Relay page:
And see this one for a dissection of the ignition switch:
A quick study of the diagrams will prove Seth's assertions. Honda calls the
ACC terminal "IG2".
What would you be tying to ground?
You want to provide 12V to the starter circuit when the button is pushed.
What are you using for a button? Will it be able to handle the current
you're going to put through it?
You want to use a relay for this. Your button will activate the relay and
the relay will provide 12v to the starter circuit.
If you don't know how to use and wire a relay, stop right now. I will not
be party to a car fire.
all this reminds me of an old clunker i had with a defective ignition
lock. long story short, removed the switch from the back of the key
barrel and hid it up under the dash so it wasn't dependent on the key.
no problems, just rotate the switch to operate, just like when it was
attached to the key barrel, right? and it worked for me just fine.
then, i lend the car to my sister. i show her where the switch is
located, start the car for her, no problem. she drives away. a couple
of hours later, she comes back and says "your car's making a funny
noise". cringing, i go outside, start the car. no problems. finally,
walking through every step of what had happened, she'd started the car
ok, but hadn't returned the switch to the "run" position after the
"start" position. when connected to the key barrel, this wasn't a
problem because it's spring loaded, and as soon as you release the key,
it springs back to the correct position. but the switch on its own
wasn't spring loaded, and she'd driven nearly 40 miles with starter
moral of the story: don't assume a damned thing when making mods like
this. i'd assumed it was obvious what to do about the starter, but
the thing the op has to look out for is re-wiring and not having
fail-safe operation, i.e. being able to run the starter motor
inadvertently. connected to the rest of the ignition switch assembly,
the starter can't be switched on when the ignition is off or the motor's
not ready to be started. or when the steering lock is disengaged.
independent wiring of a starter switch has none of these safeguards.
the only safe way to do it is to have the starter button in series with
the ignition switch starter contacts, but that kind of defeats the point.
The factory ignition switch (which works wonderfully, by the way) has two
power feeds. Depending on its internal contacts, it distributes that power
to the various devices it wants to give juice to. Those devices have their
own grounds which are used once the electricity has done its work inside
When you turn the ignition key, you are changing the positions of the
contacts inside the ignition switch. This decides what will get power, and
what will not.
When the key is turned to "II", one of the live wires at the back of the
ignition switch will go dead, and another wire -- which *had* been dead --
will suddenly come alive. That now-live one is the one which you need to
use for your button.
Basically, instead of the power routing through the ignition switch, then
to that newly-live wire, it will bypass the ignition switch contact
entirely and go through your button instead.
But Seth is right again. The starter draws an enormous amount of current.
If your button is inadequate for the load, it (and its wires) will
overheat, melt and risk a fire. Ever seen a car on fire?
Why do you want a starter button anyway? To make the car look more like a
racer? Because you think it would be cool?
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