September 20, 2021

How To: Push Button Start

I have been asked numerous times, most recently on one of my YouTube videos, on how I wired up my push button start. You yourself may have found that when searching exactly how to do this, it is very difficult to find information. That is because of a couple of reasons. There are many different combinations of ways to do this. Some methods utilize a relay, some still require a key, and some use toggle switches to simulate the OFF/ACC/ON/START functions. There are also endless possibilities on where to tap into for power to feed your toggle switches and/or push button. And another large factor is that for whatever reason, there seems to be multiple different wire colors for the ignition switch between years, models, engines, drivetrains, trims, etc.

Eventually, I will touch on a few of the basic ways to install a push button start in your 1G DSM. For now, I will mainly focus on how to wire up a push button start while eliminating the key assembly and not using a relay.

This tech article is based off of a 1G with 1G pinouts and 1G wire colors. For a 2G, the same process applies, but has one wire with a different color, which is the starter wire. The 1G starter wire color is black/yellow. On a 2G, the starter wire color is black/red. All other wire colors SHOULD be the same. Also note, I do not know if the pin locations are the same between a 1G and 2G.

Words By: AJ Hunsinger // Images By AJ Hunsinger

Our ignition switches have 6 different pins. Below is a simple diagram of the pin layout from the harness/plug.

The view of pins in the above diagram is on the ignition side of the harness. The main wiring harness plugs into the ignition harness. Pinout above is on just the ignition side. Wire colors could be different on the main wiring harness side. Main harness side also has 6 complete pins where as pin 4 on the ignition side could be empty. Literally 90% of the confusion with the push button start is identifying pins and matching up correct wire colors on the correct plug. The wire colors below may or may not be correct for your 1G. These wire colors seem to vary between models.

  • PIN 1- IG1: This wire powers your ignition, MPI, starter, etc. (black/white on 1G)
  • PIN 2- Starter wire.  (black/yellow on most or all DSM’s)
  • PIN 3- 12V Constant (white or black wire on 1G)
  • PIN 4- No pin on this side of the ignition harness. Some have a wire here but all we know is that it is not needed and stands for “R” in the diagram. 
  • PIN 5- IG2: This wire powers your heater controls, AC controls, etc. (should be blue/black OR blue/red wire on 1G)
  • PIN 6- Accessory: This wire powers all other accessories in the vehicle like radio, windows, doors, etc. (blue wire in 1G)

Now, you need to figure out what style push button start you want to use. First, I will discuss what is needed to use toggle switches and a push button to utilize all the functions in the pins above, with out a key. Really though, if you are going to go through all the work to install a push button but still have to use the key, what’s the point?

Simple Push Button With Key

One good thing you could take from this article is how to wire up just the push button start if part of your ignition switch fails and won’t allow the key to start the car. You would then simply connect one terminal of the push button start to 12v constant, while the other terminal would run directly to the starter solenoid terminal (located on the starter).

Push Button, Toggle Switches, No Key

If you decide to eliminate the need to use your key, you should begin by removing your key lock and cylinder. I don’t really want to get into too much detail on the process of removing your key cylinder, but I did take a few pictures to help you through it. You can also unplug your ignition switch and leave the key in the ON position.

To remove the key cylinder, you must first remove the lower interior panel below the steering wheel to gain access to the key and ignition switch.

Once you get all the panels out of the way, remove this small phillips head screw that holds the key illumination ring.

Next, locate the hole in the bottom, near the hole the screw was in. This is your locking pin hole. With your key in, turn the key to the ON position. Then, stick a screwdriver into the locking pin hole and pull the key out. The key will come out with the entire key cylinder. If you find that the key and cylinder will not come out, try turning the key to the ACC position.

Here are a couple of pictures of the ignition switch plugs you need to locate.

The blue plug (shown above) is the plug you need to compare wire colors to in the previous pinout diagram.

The black plug in the above picture is the main harness side. The pinout does NOT go with this plug.

With your key lock and cylinder removed, unplug your ignition switch (6 pin connector as shown above). Next, you will need to run each required wire individually to a toggle switch.

  • PIN 6- Accessory: Connect this wire to one terminal of a toggle switch. Connect the other terminal of the toggle switch to 12v constant power. This toggle switch flipped to the ON position will simulate the key being in the ACC position.
  • PIN 5- IG2: Connect this wire to one terminal of a toggle switch. Connect the other terminal of the toggle switch to 12v constant power. This toggle switch flipped to the ON position will simulate the key being in the ON position. 
  • PIN 1- IG1: Connect this wire to the same toggle switch as the one above (PIN 5). This toggle switch flipped to the ON position will simulate the key also being in the ON position.

You can feed 12V constant power from PIN 1 (white wire) to ALL of your toggle switches and push button start if it is easier for your setup. For my setup, I ran individual 12V constant power wires from my distribution block (for my battery relocation) to feed my toggles and buttons, and left the white wire (PIN 1) alone. All the white wire does is feed power to the factory ignition switch/relay.

Now, you just need to install your push button start if you haven’t already. The same steps apply to this as I mentioned above with the use of a push button start while retaining the key assembly. Simply connect one end of the terminal of the push button to 12V constant and the other terminal to the starter solenoid.

Please note that doing the above method will allow you do turn the engine over with the starter at ANY time, even if all of your toggle switches are off. An easy remedy to this (if you personally have an issue with it) is to feed 12V power from a 12v switched power instead of 12V constant power. You simply run your push button start to a separate toggle switch so that the push button start will not engage the starter unless that toggle switch is flipped on.

Push Button Start, With Relay & Key

I will add content for using a push button start with a relay while retaining the key functionality in the future. 

Secondary Engine Bay Push Button Start

Another thing that I am asked frequently about is how and why I have a secondary push button located in my engine bay. As for why, it is a very handy tool, especially if you are lazy and/or don’t have a friend that can start the car for you when needed. I have used the engine bay push start on numerous occasions.

For example, when doing a first start up after a major mod, replacement, repair, etc. when I wanted to be right there in the engine bay the second it fired up, so I would be able to see any oil leaks immediately.

Or, when using one of the push-in type compression testers that you need to push down into the cylinder with your hand. If you have a buddy that can turn the key for you, it’s not that important, but if you are alone, it definitely can come in handy. It is also nice to have when you have a car that won’t idle on it’s own until warmed up, so you have to hold the throttle at the throttle body when looking over other things as the engine is running.

As to how, it is also very easy and is the same process as the push button on the inside of the car. One wire to power and the other wire to the starter solenoid. Of course, you will already have one wire going to the starter, so you just have to splice into that wire and you are good to go. If you ran your other push button to a toggle switch like I previously suggested, you can also splice into that wire for the 12V switched power.