will i need relays for this keyless setup

Hey guys, I'm working on a completely keyless on and start setup for my car. Essentially for this step, I need a switch that will turn the car ON and OFF (before starting). My friend who's done this before through the ignition harness sent me this diagram (we have the same car):



He says to have the switch send power to the to the terminals labeled Acc....so that would be line 2,3,5, and 10. So I need 4 relays total.

My other friend who's also very experienced with car electronics tells me that I won't need relays. I asked him about powering on all of the accessories and fuel pump and such, and his exact quote is:

"The car already has relays for all that. The ignition cylinder completes a simple circuit then the onboard relays do the rest. The only instance where you'd need a relay is if the toggle switch you want to use is rated for less than 20 amps."

So who is right? I'm ordering parts now and would be grateful to anyone who would be able to tell me how many relays I'd actually need to order. Thanks!

Car is a 2002 Ford Mustang GT Convertible

Use relays

And how do you intend to get past the transponder? And use fused relays

Will do, I'll order a handful of relays just in case I need extras. And howie, what do you mean get past the transponder?

The idea is that my security system transponder deactivates the security system and disengages the starter kill for 1 minute when I hit the unlock button. As long as I turn the car on and start it within 1 minute, it should work pretty well.

what if you just want to unlock your doors without the car starting?

your cars factory remote only unlocks your door, it does not allow the car to be started remotely.

Your car needs to "see" your key in the ignition before the starter will engage. This is called PATS

(Passive Anti-Theft System) or you need to add a transponder module to trick the car into thinking the key is in the ignition, thus allowing your car to start.

It is best to install an aftermarket keyless remote start system.

Benefits: Only about $75, easier to install than what you are talking about, you get 2 new transmitters that will out perform your factory transmitters

Unless I am misunderstanding exactly what you are trying to do, I can see alot of bugs in your idea for your car.

Namely, what is gonna activate the remote start. the unlocking of your door from your factory remote?

if yes, what will happen if you hit the unlock switch on the door panel, will it engage some kind of start sequence. Sounds like your trying to engineer a product for your car that already exists.

more feedback please

Sorry I didn't explain the entire system. It's going to have all the necessary features plus a few security measures. The main components are the PKALL module, ON/OFF switch, security system, and start button.

My security system is an aftermarket system with starter kill. It's wired in so that it disengages for 60 seconds once the car is unlocked. The ON/OFF switch is only for turning on the accessories, priming the fuel pump, etc. (like turning the key from OFF to ON).

The PKALL module will send a signal to the PATS II system to allow the car to be started without the chip key (initiated by the ON/OFF switch). Then the ENGINE START button will send power to the starter motor to start the car.

To clarify, the security system is set up so that it disengages the starter kill for 60 seconds after the car is unlocked with the transmitter only.

And another question: will I need 2 relays on each accessory wire so that it turns off when I hit the momentary start button?