89 240sx alarm/horn question

[Mishkin_707]

i have a 1989 240sx coupe, 5spd SOHC. ok so i put in a viper 791vx two way alarm, i want to hook up the car horn but i was told i had to wire in a relay for the car horn to honk when the alarm went off, i dunno if any of you have experience with this but im not sure what wire from the alarm box i have to use the relay to hook the the cars horn to the alarm anyone know? thanks in advance!

[Pro ViZIon]

Did your alarm come with any instructions?

[Mishkin_707]

no it didn't, i pulled the alarm out of my eagle talon last summer because i caught someone jiggling a key in driver side door to get in my car, so i put it in my 240sx last year.

i put a horn from a lincoln town car in my 240sx cause i got tired of the crappy little stock horn that no one takes serious. i wanted to have the horn honk when my alarm went off, i asked local shop but they said they couldn't tell me info like that and want to charge me $327 to add a relay for my horn, thats a bit much to install a relay for the horn, i already put in the alarm myself

[rbpwr]

conect it to the green and white wire or see if there is a brown wire in the kick

[Mishkin_707]

Thanks for the reply rbpwr, I know which wire to use from the car, just need to know if anyone knows about viper alarms (all basically the same) to see what wires on the alarm I have to use to connect to the car

[Pro ViZIon]

They would probably have the info on they're website.

[Mishkin_707]

it gives me the wiring diagram but no info for the horn relay, someone told me i'd have to use the wire(s) on the alarm that can be hooked to the headlights to make them flash, but the wiring diagram doesn't confirm anything nor tell me what wire(s) are used for that either, i tried the 12volt website but i got flammed and banned because "people like you make us lose our jobs" not like i asked them how to install the whole alarm system. so im just stumped now.

[Mishkin_707]

no one? does broadfield still lurk this site?

[KiLLeR2001]

Hook up the brown wire from viper alarm to the green w/ white stripe wire. If you have all your ignition wires exposed you'll see a one wire harness connected to a prong. Thats the horn wire.

[Mishkin_707]

No relay? But if I do that when the alarm goes off won't that just make the horn one long loud ass honk? Cause I know the alarm siren is a 12v constant when the alarm is triggered

[KiLLeR2001]

^ Your car has a relay for the horns itself. If you hook it up as I'm saying it will not be a constant honk. It'll be a pulsating honk just as you would normally hear.

[Mishkin_707]

thanks killer, there was a two pin connector with a brown wire, i connected it with my meter and it was giving the 12V pulse i needed, worked like a charm

thanks for the help bro.

[PowerDrifter]

killer are you talking about the brown wire from the harness h1 for sirens? or the h2/8 wire for horn honk output?

[Mishkin_707]

This was a year ago.....lol are you trying to do the same thing?

[PowerDrifter]

yea didnt wanna start a new thread but yea with hella horns.

[LOUD240]

with a bosch SPDT relay
pin86 neg input from alarm
pin87 pos out to horns
pin 30&85 12 volt
pin87a nothing
this is assuming the output from alarm is pulsing
if constant out add a flasher between 87 and horns

a lot of towns consider the horn honking noise pollution and will issue a ticket

[PowerDrifter]

well i was going to wire my hella horns first following this diagram(middle of page)
DIY: Hella Horn Install - Toyota Nation Forum : Toyota Car and Truck Forums

then i guess i would cut the wire going into the siren and splice into the green/white stripe wire under the steering wheel? so i can have the hellas as horn and alarm

[KiLLeR2001]

Don't follow that diagram, that dude doesn't even have his 12V source wire fused...

First you need to find out how many amps both Hella horns pull. If its anything greater than or equal to 10A then you will need to supply your own power source with relay setup.

*** Reading online sources tell me that each horn draws 5.5A @ 12V so therefore you cannot use the stock power source wire to supply voltage to both horns. ***

So you will have to hook up a relay. Here is how you will want to hook it up...



After doing this you would simply splice into your green w/ white wire and connect it to the brown wire of the H4 harness (Viper 791xv) or the H2/8 harness for newer Viper alarms and everything will work as it should.

The brown wire on the main harness (H1 harness) goes directly to your (+) wire to the Viper siren.

[PowerDrifter]

ok thanks you guys have been very helpful, ill reply with the results when i attempt it Wednesday. and loud240 i rather get a noise ticket than my car stolen. i have the viper 5901 and have the sensitivity low and tilt sensor so it will only go off if something big happens.

so after all this i guess i cut the siren so it dosent go off also? i guess ill find out

[PowerDrifter]

worked perfectly thanks! Only the siren goes off when i arm and disarm and the horns and siren go off when the alarm goes off