Plug-in, Engine Bay Ignition Kill

The problem with alarms is that they put the start-kill relay on the ignition harness below the dash. This is exactly where a thief goes to jump start the car. Having the wires seperated out and cut makes stealing the car easier than if it had been left stock! Another problem with this is that a thief can simply bypass the start-kill by hotwiring your car downstream of it. So to combat these problems, I came up with the idea of an ignition kill that you can do in the engine bay.

The second part of this idea that I came up with was to create a plug-in start-kill that could be prepared in advance and snapped together in minutes; easily reversible without requiring you to cut your factory wiring. In order to accomplish this, you need to go to the junkyard and get some plug connectors. Then, using the junkyard plugs, you'll make an interconnect harness.

This how-to is for 88-95 Civics, 90-01 Integras, 94-97 Accords, and 92-95 Preludes. 96+ Civics don't seem to have a plug connector with an ignition wire in the engine bay.

This is the 2 pin, 10 gauge donor plug you will need to get from a junked 92-95 Civic or 92+ Integra. The black/yellow wire is the ignition wire, and the starter wire will be either black/white, or black/red depending on whether the donor car has an automatic or manual transmission. You could do the start-kill on the starter wire, but for this example I'm doing the ignition.

Locating the 2-Pin Connector

92-95 Civics and 94+ Integras have the connector behind the driver's side strut tower.

92 and 93 Integras have the connector in front of the passenger side strut tower.

90 and 91 Integras have a rounded plug connector. 88-91 Civics have the same style connector, but only at the distributer.

92-95 Preludes have their own version of this connector that is incompatible with the Civic/Integra connector. It's located in front of the passenger-side front strut tower.

94-97 Accords have the connector on the side of the passenger front strut tower. Sorry, no pic.

The same plug can be found on the distributer on almost all 88-95 Hondas/Acuras, but they're different from the plugs found on the strut towers. The distributer plug has an 18 gauge tach wire and a 10 gauge ignition wire. The strut tower plugs have a starter and an ignition wire, both 10 gauge. Do not source a connector from a distributer and try to use it at the strut tower. Also, don't put your ignition kill on the orange plug in the 94+ Integra or 96-00 Civic. Orange plugs are for ABS. The correct plug for the 94+ Integra is gray and is located behind the driver's-side strut tower.

If your car doesn't have the plug connector anywhere else, you can do your ignition kill right at the distributer. Solder the blue tach wire together just as you would with the starter wire.

You can find these plugs on the radiator fan in some vehicles. The problem is that the wire gauge is too small. To use these plugs for your ignition kill, you'd have to de-pin the wires, crimp in 10 gauge wires, and re-pin them; which is not that difficult or time consuming if you can't find any other plugs. Please do not put your ignition kill here! These are not ignition wires!

Tools

• crimpers Channel Lock 909
• wire strippers
• wire shears
• 100-120 Watt soldering iron *optional
• heat gun *optional
• screwdriver, wrenches, ratchet/sockets

Supplies

• 20/30A SPDT auto relay
• 18 gauge wire
• female quick disconnects, two 18 gauge, two 10 gauge
• small diameter split loom
• electric tape
• black zip ties
• .040 Solder or a 10 gauge butt connector
• metal tapping screw
• either an alarm, or a toggle switch and a 18 gauge ring terminal
• small diameter heat shrink *optional

Ignition Kill Wiring Diagram

This is what the wiring is going to look like. The power comes from the dash and goes to the distributer. So make sure the loop takes power to 86. If you get it backwards, you can switch the loop to 87a and 86. Depending on whether you're setting this up as a hidden kill switch or connecting it your alarm, you'll connect 85 to a switched ground. You can use a low current rocker switch if you don't have an alarm.

Now wrap the wires in split loom and electric tape, mount the relay, plug the harnesses in, connect 85 to your alarm or switch, and test it out.

This is the reality version in case you don't like the cartoon diagram. I used blue instead of green, and black instead of orange. I also crimped in a 1A diode between 85 and 86, w/the striped end on 86 (the power side). This isn't necessary, but it can prolong the lifespan of the relay.

This is how it looks after you add split loom, tape, and zip ties.

Top: Integra, Bottom: Civic. This is the end result. Just make it as inconspicuous as possible.

Test It Out

Plug your ignition kill in leaving the control wire (85) disconnected. The car should start just fine. If it doesn't, you have the ignition wire connected to the wrong pins on the relay. Ground the control wire temporarily to the chassis. The car should crank but not turn over. If it runs, you probably didn't loop 86 to the power side of the relay. Now go ahead and permanently mount the plug-in start-kill and connect the control wire to your hidden switch or to the alarm.