push button ignition/horn

Every car has an electrical system. Here's the place to learn all about it.

Moderator: 2088 bob

User avatar
bikesndbugs
Posts: 565
Joined: Fri May 27, 2016 12:15 pm
Location: san diego

push button ignition/horn

Post by bikesndbugs » Mon Jun 06, 2016 3:20 pm

So i have some ugly aftermarket ignition that hangs from my dash and the horn doesnt work so i was thinking make a push button and horn on the same button using a switch to swap from horn to starter. It could double as a sort of security system if the switch was hidden so you hit the button and instead of starting the horn honks. Is this doable? opinions?
Travis
I spend way to much time on this site

Ol'fogasaurus
Posts: 13099
Joined: Tue Nov 14, 2006 1:17 am
Location: Just north of Seattle

Re: push button ignition/horn

Post by Ol'fogasaurus » Mon Jun 06, 2016 3:58 pm

If I understand you correctly you might be going about it the hard way as would have to have another switch which would direct the power in the direction you would want.

The easy way to do it, depending on the type of switch, would be to run a wire off the accessory post on the ignition switch to a push button switch then from it to the horn. Unless it was a momentary switch I don't think in would use a toggle switch.

Lee

User avatar
bikesndbugs
Posts: 565
Joined: Fri May 27, 2016 12:15 pm
Location: san diego

Re: push button ignition/horn

Post by bikesndbugs » Mon Jun 06, 2016 5:27 pm

i was thinking the hard way but have the power directing switch hidden so it works as the hidden switch to act as a sort of a theft deturant. My dad was saying put 2 buttons one strictly horn and the other either starter or horn. That seemed very pointless to me. Wouldnt the easy way make the starter turn anytime i hit the horn button? Im not the best with electrical it confuses me
Travis
I spend way to much time on this site

Ol'fogasaurus
Posts: 13099
Joined: Tue Nov 14, 2006 1:17 am
Location: Just north of Seattle

Re: push button ignition/horn

Post by Ol'fogasaurus » Mon Jun 06, 2016 5:52 pm

Having the horn and starter on the same line is asking for trouble. Every time you hit the starter the horn would go off for the full time you were trying to start the car. Conversely, each time you hit the horn the starter would engage which would have the potential of doing great damage. With a directional switch in an emergency situation that could cause confusion and it could be set to work on the device you didn't want operate.

Two buttons that work separetly like your farther said would be best. If you had the one push button and a directional switch that still works out to being two devices.

If you have an ignition switch with a start function would reduce the number of holes needed and make your life much easier.

Good questions.

Lee

User avatar
bikesndbugs
Posts: 565
Joined: Fri May 27, 2016 12:15 pm
Location: san diego

Re: push button ignition/horn

Post by bikesndbugs » Mon Jun 06, 2016 6:31 pm

ya i was thinking a directional switch so 2 devices on one button just the switch swaps from starter to horn. its called a directional switch that is what id buy right? i have buttons for it
Travis
I spend way to much time on this site

User avatar
sideshow
Posts: 3206
Joined: Mon Oct 27, 2003 2:00 pm
Location: suth'ern oraygun yusa
Contact:

Re: push button ignition/horn

Post by sideshow » Mon Jun 06, 2016 6:47 pm

A/B switch, button feeds in, out goes to starter or horn.

Not an insane idea, but a little odd. Seems to me both the horn and starter are sometimes needed "right now" and you may tire of the dis-arming procedure.
Yeah some may call it overkill, but you can't have too much overkill.

User avatar
Marc
Moderator
Posts: 23722
Joined: Thu May 23, 2002 2:01 am
Contact:

Re: push button ignition/horn

Post by Marc » Mon Jun 06, 2016 6:58 pm

bikesndbugs wrote:ya i was thinking a directional switch so 2 devices on one button just the switch swaps from starter to horn. its called a directional switch that is what id buy right? i have buttons for it
The toggle would be called a SPDT (single-pole, double-throw). They're made in different "flavors", including spring-return - you don't want that for your intended use so skip over those. What's left is a switch that has terminals for three wires, power-in plus two outputs selected by switch position, and two switch positions (or three, with the third being "off"). Either of those would work for what you have in mind, just choose one that can handle the current draw of the starter solenoid. 30 amps is a fairly common "size" that would do fine; choose one that has screw or spade lug terminals stout enough to make it easy to connect 12AWG wires.

Sometimes a DPDT (double-pole, double-throw, with six terminals) switch only costs a bit more than a comparable SPDT. If you use one of those and the contacts go bad you can simply move the wires to the other set of terminals and be back in business...sort of an "installed spare".

A stock horn only needs 16AWG. Most ACVWs don't use any horn relay, they have a 2-terminal horn that allows power to be present on one at all times and the horn button's wired to the other one so the ground path is completed when it's pressed. It can also be used for your design, just connect a ground to one terminal and have the button (through the toggle) supply the power to the other. I would install a fuse as close as possible to the "horn" output terminal of the toggle.

There's no fuse protection provided in the stock wiring for the starter solenoid control circuit, and that's pretty much OK - just be careful to route your new wires so they aren't going to have their insulation chafed.

Ol'fogasaurus
Posts: 13099
Joined: Tue Nov 14, 2006 1:17 am
Location: Just north of Seattle

Re: push button ignition/horn

Post by Ol'fogasaurus » Mon Jun 06, 2016 7:06 pm

Marc, I don't think I was clear as I was referring to the starter switch not a directional switch.

I'm also back to having posts being full dropped or partially dropped. Getting irrated!

I still recommend circuit protection on both start and run even if VW didn't. Also use proper gage wiring.

Lee

User avatar
bikesndbugs
Posts: 565
Joined: Fri May 27, 2016 12:15 pm
Location: san diego

Re: push button ignition/horn

Post by bikesndbugs » Mon Jun 06, 2016 7:13 pm

thank you
Travis
I spend way to much time on this site

User avatar
Marc
Moderator
Posts: 23722
Joined: Thu May 23, 2002 2:01 am
Contact:

Re: push button ignition/horn

Post by Marc » Mon Jun 06, 2016 7:24 pm

How 'bout we just lose that term "directional switch" altogether until someone's talking about turn signals? IMO that's the only context for it, although personally I use "t'signal switch" instead.

With the arrangement bikesandbugs proposed, the toggle selective switch would effectively isolate the horn and solenoid. The starter would only engage when it was selected by the toggle, even if there were multiple horn buttons. The issue is that the stock horn button would no longer be effective with such a simple design since it switches the ground side of the horn circuit - the solution would be to add a relay, as is found on Karmann-Ghias, controlled by the stock horn button yet delivering power to the horn. That way you'd have the "booby-trap" feature of the horn sounding when the starter button was pressed by a potential thief, with the stock horn button remaining functional.


If you didn't need the starter button to also act as a horn button, there are several other ways that the horn could be armed to sound with a sneaker switch...none comes to mind that wouldn't need a relay, or a diode capable of handling the current.

Ol'fogasaurus
Posts: 13099
Joined: Tue Nov 14, 2006 1:17 am
Location: Just north of Seattle

Re: push button ignition/horn

Post by Ol'fogasaurus » Mon Jun 06, 2016 7:53 pm

I couldn't think of a more appropriate term as that was what he was proposing as far as I could tell. I hadn't even thought about the turn signals :oops: . I was thinking KISS which is good unless it is with someone else's wife! KISS, if someone doesn't know is Keep It Simple Stupid.

I think there is going to be a lot of learning and a bunch of quick learning on this build. We are here for you. :lol:

User avatar
bikesndbugs
Posts: 565
Joined: Fri May 27, 2016 12:15 pm
Location: san diego

Re: push button ignition/horn

Post by bikesndbugs » Mon Jun 06, 2016 9:07 pm

well my horn doesnt currently work so i would like it to do both and im gonna buy a grant steering wheel or something else soon so button will be the horn then i dont have to worry about it in the future.
The initail idea was to use a SPDT switch i just had no idea if it was made or where to get it and how much amperage it would need to handle. 30 is good and that means the button would need to handle 30 also right. I have a tendency to drift off in class and end up thinking about this stuff.

User avatar
Marc
Moderator
Posts: 23722
Joined: Thu May 23, 2002 2:01 am
Contact:

Re: push button ignition/horn

Post by Marc » Mon Jun 06, 2016 10:25 pm

Maximum "pull-in" current for a Bosch 12V starter solenoid is 35A; once the starter's engaged it should be 11A or less. So I'd consider 30A to be the minimum, heavier-duty can't hurt.

The stock horn control circuit on a Beetle is pretty basic (i.e. cheap to manufacture) and high resistance in the circuit is a frequent cause of a feeble horn. For Karmann-Ghias they went to dual horns but retained the same horn button setup; a relay was added to ensure they'd work reliably. You might consider adding one to your car too, that'd also allow you to use a single-terminal horn like most cars use.

User avatar
bikesndbugs
Posts: 565
Joined: Fri May 27, 2016 12:15 pm
Location: san diego

Re: push button ignition/horn

Post by bikesndbugs » Tue Jun 07, 2016 12:09 am

okay i might just buy a cheap air horn kit from harbor freight. wiring im very new at i learn quick though just haven't messsed with it too much. The relay creates better flow right? and thicker wire = better flow im probobly gonna have to clean up alot of wiring anyways in the car so itll be a learning experience. update just watched a you tube video now i get it gonna watch some more tomorrow on random wiring stuff
Travis
I spend way to much time on this site

Ol'fogasaurus
Posts: 13099
Joined: Tue Nov 14, 2006 1:17 am
Location: Just north of Seattle

Re: push button ignition/horn

Post by Ol'fogasaurus » Tue Jun 07, 2016 12:45 am

Be sure of your grounds, the ground is where the work is done. Tired metal, and that includes wires, needs to be checked often in older cars.

Do a search for a voltage drop chat and put it in you favorites for quick reference.

Lee

Post Reply