external acc switch to bypass using key

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URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=108161
Printed Date: May 10, 2024 at 3:19 AM

Topic: external acc switch to bypass using key

Posted By: redstealthrt
Subject: external acc switch to bypass using key
Date Posted: October 15, 2008 at 1:39 AM

Hello everyone i am looking in trying to hook up a switch so that i can roll my windows up/down without having to put the key into the ignition and turn it to "ACC/ON" mode in order to do so. Could someone share their knowledge with me on how to go about doing something like this?

Thanks! :)

David

Replies:

Posted By: ckeeler
Date Posted: October 15, 2008 at 9:54 AM

can you tell us what vehicle you want to do this to?

Posted By: redstealthrt
Date Posted: October 15, 2008 at 11:25 AM

Sure. A 1992 Dodge Stealth R/T Twin Turbo. I already know what wires there are for the ACC/IGN and so on, i just need to know what all needs to be hooked up to a switch in order for me to be able to use that instead of my key to be placed in the ACC or "on" position.

Thanks,
David

Posted By: ckeeler
Date Posted: October 15, 2008 at 11:37 AM

with a fused lead, connect a wire from 12v conatant into one side of a toggle or rocker switch. connect the other side of the switch to the acc wire in the ignition harness. thats it.

Posted By: redstealthrt
Date Posted: October 15, 2008 at 11:41 AM

ckeeler wrote:

with a fused lead, connect a wire from 12v conatant into one side of a toggle or rocker switch. connect the other side of the switch to the acc wire in the ignition harness. thats it.

Wow ckeeler, really? That's all that i would have to do?? What would i need to do in order to start it then if i have that switch plus a push button switch to start it?

David

Posted By: ckeeler
Date Posted: October 15, 2008 at 12:02 PM

then... you also would need another switch to trigger a couple of relays(one for each ignition wire) that would power the ignition wires. then when you pushed your start button you'd be running. use 10ga or 12ga wire to do these circuits. also use 10ga or 12ga for the toggle you wanted to use for the acc on to roll up your windows. unless you disable you steering lock though, you still need a key anyway. and if you did disable the lock, without a security system, or RFID system, anybody could just break a window, flip the switches, push the start button and drive away. just something you might consider.

Posted By: redstealthrt
Date Posted: October 15, 2008 at 12:12 PM

Here is the schema for my car...
posted_image

Posted By: ckeeler
Date Posted: October 15, 2008 at 12:46 PM

wire the ignition relays as follows: 12v from the white wire in the ignition harness into the rocker switch, out of the switch to term 86 of 1st relay for ign1 and term 86 of 2nd relay for ign2, term 85 of both relays to ground, term 87 of 1st relay to BLACK/ white in the ignition harness(use 10ga wire), 87 of 2nd relay to blue/black in the ignition harness(use 10ga wire), term 30 on both relays connect each to their own separate 10ga wire and connect to the battery(fuse them at the battery with 20a fuses).

Posted By: redstealthrt
Date Posted: October 15, 2008 at 4:01 PM

ckeeler thank you for clearing it all up for me :)

For the rocker switch.. would i need a DPDT, SPDT or just a Momentary one?

And for the relays i will be using these: posted_image

(Or equivalent). Power Relay, 12v, SPDT, PCB Mount, 10/12A 125VAC, 10A 277VAC, 1/4HP 125VAC

Do i need a more powerful relay that what i listed?

David

Posted By: ckeeler
Date Posted: October 15, 2008 at 4:09 PM

for the acc and ign rocker switches, just use a standard SPST rocker switch. if you want to, you can even get ones that light when they are on. use a momentary push or rocker only for the starter. use standard 12vdc SPDT bosch, hella, or potter & brumfield relays, they should be able to hold 30amps of current each between terminal 87 and 30. actually, any brand will work, those i named are just the best.

Posted By: redstealthrt
Date Posted: October 15, 2008 at 4:18 PM

ckeeler: Where does the switch for the starter go then (hook-up wise)?

Also, I am looking to put the relay on a pcb layout.. Do u happen to know any? This is the only one i could find here but its rated at 10A at 250 VAC... is that enough of does it need to be 30A?

David

Posted By: redstealthrt
Date Posted: October 15, 2008 at 4:26 PM

And here i draw up what i think u r talking about posted_image

David

Posted By: ckeeler
Date Posted: October 15, 2008 at 4:33 PM

exacto mundo dude!

Posted By: ckeeler
Date Posted: October 15, 2008 at 4:36 PM

the pcb setups are more for current needs less then what you are probebl gonna be pulling. use a power in off white in the ign harness into your momentary switch and go right back out to the starter wire.

Posted By: redstealthrt
Date Posted: October 15, 2008 at 4:37 PM

So in the drawing of mine, where does the switch for the starter go?

Posted By: redstealthrt
Date Posted: October 15, 2008 at 4:43 PM

Ok here is the drawing of the starter button:
posted_image

Correct?

David

Posted By: ckeeler
Date Posted: October 15, 2008 at 5:06 PM

yep,thats it posted_image

Posted By: redstealthrt
Date Posted: October 15, 2008 at 5:13 PM

Well gee someone give me a cookie posted_image

So ckeeler the link i posted for the relay is a good enough relay to use with all of this?

David

Posted By: redstealthrt
Date Posted: October 15, 2008 at 5:19 PM

Here is the link since the list i posted in a few post above ended up not working...

the link

David

Posted By: ckeeler
Date Posted: October 15, 2008 at 5:38 PM

it'll work fine

Posted By: redstealthrt
Date Posted: October 15, 2008 at 5:50 PM

Ok ckeeler this is what i will be going with: The Relay

Its a RELAY AUTO SPDT 30A 12VDC PCB

And from the schema of it... i hope i got the pins correct... Double check me if u please:
posted_image

Pin 2/5 = Coil (a.k.a. 86/85)
Pin 4   = Common (a.k.a. 30)
Pin 1   = N/C (a.k.a. 87a)
Pin 3   = N/O (a.k.a. 87)

Question is for the Pin 1 and Pin 3.. which one do i us for the B/W wire and B/B wire?

David

Posted By: ckeeler
Date Posted: October 15, 2008 at 6:01 PM

you will need 2 of these, one for each ign wire. pin 4 will go to power, pin 3 will go to the ign wires, do not use pin 1.

Posted By: redstealthrt
Date Posted: October 15, 2008 at 6:14 PM

Ok heres another check with a awesome drawing skills posted_image

David

Posted By: redstealthrt
Date Posted: October 15, 2008 at 6:20 PM

Oh yeah, does the 12v W HAVE TO BE from the white wire? Or could i use some other 12v wire in the car?

David

Posted By: ckeeler
Date Posted: October 16, 2008 at 11:27 AM

you can get it from anywhere. if you get it off the battery though, fuse it, close to the battery.

Posted By: redstealthrt
Date Posted: October 16, 2008 at 12:15 PM

Ok ckeeler thanks so much for the information you have given to me! posted_image

But i have one more question... What wire would i need to find to check to see if the car was running or not? Like if it wasn't running then it would have 0v. If it was running then it would have Xv going through the wire.

David

Posted By: ckeeler
Date Posted: October 16, 2008 at 12:20 PM

well, do you mean the ignition is on and powered? or the actual engine itself is running and making rpm's?

Posted By: redstealthrt
Date Posted: October 16, 2008 at 12:21 PM

ckeeler: Sorry, when the engine is running posted_image

David

Posted By: ckeeler
Date Posted: October 16, 2008 at 12:51 PM

well.....2 ways. you can use the tach wire but that tests with AC voltage, not DC. or you can get a 12v signal from the power that goes into the fuel pump in the fuel tank. it will show 12v for a second or two when the ignition is first turned on then go off, and not have voltage on it again unless the engine is running. i dont know the wire color, you will have to test for it at the pump.

Posted By: redstealthrt
Date Posted: December 17, 2008 at 8:37 PM

Ok, coming back to this:

Once i hook the wires up to the relays and i flip the switch, i take it that the car should start within 5 secs or less? Once the car has started with the momentary switch, do i cut the power to both relays?

David

Posted By: ckeeler
Date Posted: December 18, 2008 at 7:03 PM

the relays need to stay powered to keep the ignition on

Posted By: redstealthrt
Date Posted: December 18, 2008 at 7:08 PM

Ah, ok ckeeler! :)

David

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