Hopefully you aren't starting with an ignition harness like this..........it's obvious that there has been something installed here before based on the butt connectors(which should never be used on an ignition harness in my opinion) so we will need to clean this up as we go.
Remote Start Pre-wire
I typically like to do some wiring of the remote start before I actually install it in a car. Essentially remove and or cap off wires that will not be used during the installation, as well as making as many connections as possible of ignition/immobilizer bypasses and interfaces. I'm trying to make as few in car connections as possible and make any future potential troubleshooting easier.(Hopefully not needed :) )
*Disclaimer*: These are the connections made in out particular car. Always, always, always double check any electrical connections with a digital multimeter (DMM) or computer/air bag safe test light.
|Wire Function||1990 Miata Wire Color||Remote Start Wire Color|
|Starter||Black / Blue||Purple|
|Second Ignition||Black / Red||Pink / White|
|Accessory||Black / White||Orange|
|Parking Lights (-)||Red / Black||White|
|Tachometer||Yellow / Blue||Purple / White|
Quick snapshot of where the brain is mounted. Up above the gas pedal secured with four zip-ties. Perfectly acceptable location for a remote start only installation as this, terrible idea if this were an alarm!
Ignition connections soldered and taped up. You'll notice that the ignition harness is unplugged from the key cylinder. This usually makes things a lot easier when making your connections, but one thing to keep in mind is to make sure you have/leave enough slack on your remote start wires to make your connections and still be able to plug the harness back in!
Antenna was installed low on the windshield to keep a clean look. For our application, 99% of the time the car will be relatively close to where we will be so cutting down on range isn't a concern. For maximum efficiency, typically it is best to install the antenna up around the rear view mirror, or at least the top of the pillar on the driver's side.
Parking light wire connects to the back of the dimmer switch on the dash
Tachometer wire. Most remote starts now have a feature called "voltage checking" where essentially the remote start "checks" the vehicle voltage after attempting to start the car. If it sees a voltage higher than it was at rest, it knows the car is running and it does not attempt to start the car again. If it sees the same voltage, it will attempt to crank the car again.
On older cars like this I like to run the tachometer wire off the remote start that reads actual vehicle RPM pulses. Sometimes these older cars are grumpy and need a few extra milliseconds of crank time to get going when it's cold :). On the Miata we decided to pickup this wire at the back of the gauge cluster.
Brake input/shutdown. This wire is responsible for turning the remote start off once you are in the car. Press it without the key inserted into the cylinder and turned to the "ignition" position, and the car shuts off.(And keeping any would-be thieves at bay)
If you have an automatic transmission car, this next step is not necessary. We wired in a SPDT relay to bypass the clutch switch during remote start. ***NOTE: We do not have a neutral safety switch installed, nor do we plan to. If you perform this modification, and you try to remote start your car with it still in gear, the CAR WILL MOVE FORWARD. We have tested this in some cars and while cranking we have seen cars move 30+ feet!! Be aware and use caution when remote starting a manual transmission car. If your car crashed into something/someone, we are NOT responsible! You have been warned!*** You can see the Scosche relay we wired in and installed.
Black/Blue & Black/Red wires are the ones that need to be "jumped" or connected together for the car to try and crank.(Simulating the clutch being depressed and the switch connected to it completing the circuit.)
Here is how we wired up the relay.