Start button parts
The master diagram: PRINT THIS!
Study the diagram for a moment. It shows insulated 12 gauge (yellow) bullet connectors, and I'd certainly suggest using
something like that. This diagram also shows both the colors of the factory wiring harness, and the colors
on the back of your relay harness. Refer to the above master diagram for a visual
reference to all associated wiring colors not included on this diagram. I used 12 gauge wire for all of my
relay-to-factory connections and 18 gauge wire (note the blue connectors) for all my start button connections. Finally, notice that there's a ring terminal that says "Ground to steering
column." There's two large bolts on the steering column, holding it in place, that are excellent grounds. You
can either use a large ring terminal, or a small fork terminal wedged under one of these large bolts.
Wiring the relay
Wiring your relay is incredibly easy if you use on of the 5 pin relay sockets that Parts Express sells and
I'd highly suggest using one. If you are using it, the following list will be useful.
The relay socket makes life easy.
Next, you get to slice into your factory wiring. You only cut two wires, but it still requires some planning.
If not already done, remove the knee guard from below the steering column.
Factory wiring harness modification
This little guy lives to the left side of the steering column (that's the opposite side of the key switch) and has two small
plugs connecting it. Unplug both. The 6 prong harness with the beefy wires is the one you'll be modifying. The small harness
is for the door buzzer.
The starter switch wiring harness.
The wires you want are on either end of the top side of this plug. The IG2 wire is black with a red stripe (on the left). The
ST wire is white with a black stripe.
Do not cut right at the key switch, rather cut an inch or more away. Make your cut and crimp on your insulated
terminals as shown in the photo above. Why are you doing this? When (not if) your relay fails, you
want to be able to quickly reconnect everything in the factory configuration. You'll just unplug the factory
wires from your relay socket and plug them back into each other. Relays fail after x number of uses. In
12 years, I've had replaced the start button relay twice.
Cut and crimp.
Once you've got the wires sliced and the correct crimps installed, just connect the relay and socket combo. Three wires will get
connected and the short white/black one nearest the switch will just dangle. Then bolt the ground connection to the steering column.
At this point, you can either let the relay dangle or you can tie it up and out of the way with some zipties.
Plug in the relay.
You'll need the internal PC power connector you see in the above photo. This is
the one that connects to a small 3.5 inch floppy drive that computers used to have. It's a four prong connector, and the S2000 button is
a 5 prong, but since only 3 of those prongs actually do anything, we're ok. Just plug the power connector
onto the button and clip off the fourth wire. You'll need to extend these wires to meet their respective source
wires, but we'll do that in a later step.
Wiring the back of the starter button
As you can see from the diagram, the prongs are labeled 1, 2, and 3, starting from the right. The lower picture
is my original hacked-up starter button housing. It serves only to show which prongs are which. Don't let it confuse
you. You'll be connecting #1 to pin 85 on your relay (the black wire). #2 and #3 provide power and ground for the little
light inside the button. We'll get power from the lighter and ground from the e-brake. Why? We use the handbrake
ground so that the little "ENGINE START" light will only be lit when the hand brake is in the up position.
Connect your start button to the relay now. In case the many many diagrams above didn't tell you enough times, run the black
wire from the relay (pin 85) to the red wire on the start button (pin 1). I needed a short jumper wire to bridge the gap. About
a foot of 22 gauge wire did the trick. This wire is just activating the relay, so there's no need for beefy 12 gauge.
Yet another start button connection diagram.
Now, go to the bottom of your center cluster and dig around for the cigar lighter wiring harness. It has two
wires, a yellow and a black. The non-black is your power wire. I'd recommend verifying which is the power wire with your multimeter. Run a lead from your start button
wire to this power wire and tap into it. Since my button and the lighter were so close, I was able to get away with
using the small wire on the A-drive connector.
Connect to the lighter power.
Find the single wire coming out of your hand brake (emergency brake). There's only one. This is the wire that
tells the dash light to turn on or not. It's just a ground wire. Connect it to wire #3 on your S2000 start button.
I had to add a short jumper wire for this connection as well. About a foot of 22 gauge wire (in blue this time). And a vampire
tap. I usually hate vampire taps, but for these small gauge connections, they usually work quite well.
Connect the hand brake wire.
Much like step 1, you're pretty much on your own here. The lighter can be relocated into your glove box
pretty easily. A trip to your friendly local auto parts store should get you a weather-proof lighter housing that you
can mount anywhere. Just connect it to the factory lighter wires and you're set.
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