relay auto start

hello to all... ive been installing quite some time on the side as a hobby and would like to take a shot at wiring an auto start from a relay combonation... ive installed numerous modules and love the units but this install is more for my piece of mind knowing i can do this rather than ease for myself or the user. ive done alot but never have done everything... im trying to get there eventually...

this is the piece of work as i see it here on the12volt... my questions.. are.. the ignition imputs... one is a key side and the other is a vehicle side... for what reason would i have both of these connections when using a module i never ran by anything of this nature... im taking this is the true igniton wire and i would be cutting it as if a were doing a starter kill and i have my key side / starter side... am i correct in thinking this?

and also.. i swore that ive seen this pulled off with fewer relays... or am i wrong? because god knows i do not want to try to stuff that in my dash! after i learn this i will be following up with that... 1 output to 4 output diagram next.. i hope i can find the answers im looking for. thank you in advance for your efforts and advice...

i guess you meant this picture?

I wouldn't really use that.  I would buy a remote starter module instead...that way you  know it will work, and you'll have more features (like tach monitoring, shut down after so many minutes, stuff like that).

He already said why he wants to do this.

dxp, I've studied this diagram a little bit; it sure is complex and fascinating at the same time.  Anyway, look at the bottom right relay.  Turning the car's key to Run activates this relay, which in turn places a ground on the light blue wire, which deactivates the remote start, so the car can then be driven under its own power.

I created this long before remote starts where readily available as they are today. There are other shut down and safety features I purposely did not include in this diagram and I only show it as a reference to show what can be done with relays and a little imagination. It is not intended nor recommended to be used in place of the units available today, but only as a challenge and learning experience for installers and enthusiasts.

With all of the aftermarket units that are available today and for as little as they cost I strongly recommend using them instead of making your own. However, if you're up to the challenge, keep in mind the diagram only shows the basics of my design to get you started. It does not show diodes across the coils of the relays nor any of the other safety features that you should incorporate such as monitoring tach signal, safety/neutral wire, brake & parking brake inhibits, a timer, a single output to start and stop the unit, etc.

BTW, the time it takes to wire all of these relays with the additional features before you even install it will be about the same amount of time or more that it takes to install an aftermarket unit with all the goodies included. 

the12volt