Could you take a look at my diagram?

Thread Starter

Stuart McWilliams

Joined Aug 24, 2016
3
I'm currently rewiring my 90 Miata and installing a push-to-start button to replace the key cylinder and go completely keyless, because racecar. The way it will work is there will be two separate switches, first is a toggle on/off and the other will be a momentary switch. The on/off will activate the ignition circuit, and then the momentary is held and fires the starter. I'll have to deal with the ignition lock as well to be completely keyless but that's mechanical.

I'm an amateur when it comes to wiring. I have experience with basic audio wiring and such but did a lot of research and reading to try and draw this up. I was just hoping to get a second opinion on my diagram as well as make sure I'm reading factory wiring diagram correctly.

I included a pic of the wiring diagram for the ignition switch. I drew up the diagram that includes four relays, 2 SPDT and 2 SPST, but I feel like it could be done more efficiently and I also want to make sure my ground leaving the coils of the relays won't short the whole system and if I should use an external 12v source to tie into the ignition switch.MYuZUO9.jpg tTlPouu.png
 

gerty

Joined Aug 30, 2007
1,305
You appear to have your relay coils wired in series. Each coil should have its own ground. what are the symbols above the relays?
edit: Why is there 2 batt designators, do you have two batteries?
 

Thread Starter

Stuart McWilliams

Joined Aug 24, 2016
3
Yiu appear to have your relay coils wired in series. Each coil should have its own ground. what are the symbols above the relays?
edit: Why is there 2 batt designators, do you have two batteries?
I had them wired in series because both relays would be activating when I hit their respective switches, but I guess I should wire in sequence and have separate grounds? That make sense. The symbols above the two relays in the middle are grounds.

Above those are my switches. Guess I should have clarified that. The one on the left is the toggle and right is the momentary.

Those six wires at the top are the harness that plugs into the ignition switch. I believe there are two power wires because the high amount of voltage going through the wires, and on the factory diagram it shows that B1 powers IG1/ACC and B2 powers IG2 and the starter so I had it wired exactly that way.
 

Thread Starter

Stuart McWilliams

Joined Aug 24, 2016
3
You don't need any relays for this; the original ignition switch managed to work without them.
That's why I was feeling like it was overcomplicated. I read elsewhere that the amount of voltage would overpower a switch and I need my car to start reliably. Every online writeup I've seen uses a relay but all of them still use the key for ignition and the push button is only for the starter. I'm wanting to go completely keyless. Also, I have a lot of space behind where the panel will go, since it's going where my HVAC control was and all of that is going away.
 

blocco a spirale

Joined Jun 18, 2008
1,546
That's why I was feeling like it was overcomplicated. I read elsewhere that the amount of voltage would overpower a switch and I need my car to start reliably. Every online writeup I've seen uses a relay but all of them still use the key for ignition and the push button is only for the starter. I'm wanting to go completely keyless. Also, I have a lot of space behind where the panel will go, since it's going where my HVAC control was and all of that is going away.
As long as the switch is rated for the current there won't be a problem. You would only need a relay if the type of switch you want to use cannot handle the current so check the current with a meter.
 
Top