wiring up new horns, need help with relays

[ufvj2172]

can someone finish this diagram for me?

keep in mind, i will have TWO sets of horns, and TWO relays. so i need to know how to hook up the one switch for both sets of horns, to both relays.

also, i just need one fuse for both power wires going to the relays right? what amperage should i get?

the horns are Hella Supertone 85115's.

Click to read more...

 

[achapman 10+ year member]

Well 86 should be the trigger wire, and 87 will be the normally open contact.

So 87 will go to the horns, and 86 will get the positive wire from the switch that will tell the relay to open the contact for 87.

 

[Trey803 5,000+ posts]

air horns???

 

[achapman 10+ year member]

The Supertone's aren't air horns.

Find out how much amperage they pull, and pick a fuse according to that.

 

[starkfu 10+ year member]

it would be easier to use 85 or 86 as a negative trigger from whatever is controlling it and tie the opposite 85 or 86 to the positive feed on pin 30.

 

[ufvj2172]

30 = fused wire from batt

85 = ground

86 = positive switch wire

87 = horns

is that right?

http://www.rallylights.com/hella/supertone_horn.asp

says max power draw is 72w. i dont see anything about how many amps it draws //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

im going to hook up my own switch, so if i get one from autozone, just hook positve to 86 on the relay, and then ground the switch too?

ive seen ppl using 10a fuses, or 20a, what ill prally go 15. lol

 

[achapman 10+ year member]

Since you are using 4 horns, I'd go 20 amps.

Hmmm, you could probably put the switch on the grounds. Is there a switch that can handle 20 amps going through it from autozone?

But I don't understand the point of the switch if you have the relay? '

You could just wire them and put a switch on the ground. Then hit the switch when you want them to honk....Or am I missing something?

 

[starkfu 10+ year member]

30 = fused wire from batt85 = ground

86 = positive switch wire

87 = horns

is that right?

http://www.rallylights.com/hella/supertone_horn.asp

says max power draw is 72w. i dont see anything about how many amps it draws //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

im going to hook up my own switch, so if i get one from autozone, just hook positve to 86 on the relay, and then ground the switch too?

ive seen ppl using 10a fuses, or 20a, what ill prally go 15. lol

I would do this

30 = positive fused feed

85 = looped off of pin 30 positive

86 = to your switch (then ground the other side of the switch)

87 = to horns.

if you are soldering, just solder a short piece of wire from pin 30 to 85, then connect your fused feed to pin 30 only, send 87 out to your horns, then connect pin 86 to your switch, connect the other side of you switch to ground. I never like having positve voltage to my switches, if you get a short or frayed wire against ground with a positive feed, that is how fires start. With a negative trigger, if it frays or shorts, it does so to ground, which it already is.

 

[ufvj2172]

Since you are using 4 horns, I'd go 20 amps.
Hmmm, you could probably put the switch on the grounds. Is there a switch that can handle 20 amps going through it from autozone?

But I don't understand the point of the switch if you have the relay? '

You could just wire them and put a switch on the ground. Then hit the switch when you want them to honk....Or am I missing something?

well im gonna have 2 relays, so i was thinking a 10a fuse each pair of horns?

 

[ufvj2172]

I would do this
30 = positive fused feed

85 = looped off of pin 30 positive

86 = to your switch (then ground the other side of the switch)

87 = to horns.

if you are soldering, just solder a short piece of wire from pin 30 to 85, then connect your fused feed to pin 30 only, send 87 out to your horns, then connect pin 86 to your switch, connect the other side of you switch to ground. I never like having positve voltage to my switches, if you get a short or frayed wire against ground with a positive feed, that is how fires start. With a negative trigger, if it frays or shorts, it does so to ground, which it already is.

i thought the relay has to be grounded (pin 85)?

so since im gonna have 2 relays, one for each pair of horns, this is how you think i should do it...

relay one:

30 = fused from batt

85 = connect wire from 30 and hook that to 85

86 = to positive on switch

87 = to a pair of horns

?

why wouldnt i just ground 85, rather than loop it from the 12v power from pin 30, and still connect postive 86 to switch, and ground switch....

 

[spoonraker 10+ year member]

FYI most switches can carry up to 30 amps, you might not even need a relay.

 

[mlstrass 5,000+ posts]

For momentary use just a switch would be fine, or you can get higher amp rated switches. Most auto store lighted toggles are rated at 15amps.

Why would you connect 30(power in) to 85(ground)? Just wire as described in post #6 and do 2 relays that way. Or get a 30amp momentary toggle or push button switch. If you have a NAPA auto parts store they should have them.

 

[starkfu 10+ year member]

pins 85 and 86 on a relay are interchangeable, you don't have to necessarily ground or trigger either one.

when 85 is hooked to positive and 86 get's triggered negative, the relay connects pin 30 from 87a to 87

now just as easily, 86 could be hooked to positive and 85 get the negative trigger, or 86 grounded and 85 with a positive trigger, or 85 to ground and 86 with a positive trigger.

THE BEST WAY to do it is use a permanent positive polarity on 85 or 86, then use a negative trigger to the pin you didn't hook to positive, make sense?

The whole point here is to get potential across the electromagnetic switch and change the pole that pin 30 gets connected to, thus why it is called a single throw double pole relay.

Think of it as a rail switch, where two tracks meet one. If you are coming down the single line and see a big Y of tracks in front of you, then you are on pin 30 of a relay. Now the normal setting of the switch has you going left (pin 87a), but if the conductor radios to have a switch thrown (potential across 85 and 86, doesn't matter what get's + or -) then the train will go right (pin 87).

Hope this helps.

AS FAR AS USING a high current switch (as opposed to a relay), don't. high current switches burn cars to the ground and it isn't very proper. switches should only be used as triggers.