Horn connect to siren

Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=40917
Printed Date: May 14, 2025 at 7:59 PM

Topic: Horn connect to siren

Posted By: mikelee223
Subject: Horn connect to siren
Date Posted: October 14, 2004 at 9:52 PM

Can I connect the negative of the horn to the negative to the siren on alarm for the horn and siren to go off? Will the horn be constant or on and off like the siren?

But actually, I do not want to connect to parking light, because i have a remote start and the light flash when car is in remote start.

Thanks for an insight.

Replies:

Posted By: Teken
Date Posted: October 14, 2004 at 10:13 PM

You would need a relay to do it safely, assuming the OEM horn is not using a relay in the circuit. You would also need to know the polarity of the OEM horn.

If it is the opposite, then you simply need to add a relay to convert the polarity.

Positive (+) to (-) output

86 & 87 = Ground

85 = (+) Positive trigger to be changed to a (-)

30 = (-) Negative output

Negative (-) to (+) output

86 & 87 to Fused 12 volts

85 = (-) Negative trigger to be changed to a (+)

30 = (+) Positive output

Regards

EVIL Teken . . .

Posted By: Teken
Date Posted: October 14, 2004 at 10:17 PM

To increase the alarms positive output current ability wire, *add in* the appropiate relay of your choice, and wire it like this.

87 = Fused +12 VDC constant

86 = Ground (-)

85 = Positive siren output from alarm system.

30 = Connect to (+) the horn / siren together.

Regards

EVIL Teken . . .

Posted By: mikelee223
Date Posted: October 14, 2004 at 10:19 PM

Where can i buy them relays? Sorry for the stupid questions. Also, My car is an Acura 3.2 TL '00.

Posted By: Teken
Date Posted: October 14, 2004 at 10:29 PM

Buy the relays on line or at any automotive store. Your horn is the green / light blue wire and can be found at the steering wheel harness. It is also (-) negative switching.

Regards

EVIL Teken . . .

Posted By: mikelee223
Date Posted: October 14, 2004 at 10:45 PM

So i would follow the

Negative (-) to (+) output

86 & 87 to Fused 12 volts ( 12V from alarm? )

85 = (-) Negative trigger to be changed to a (+) ( Neg. Horn Wire )

30 = (+) Positive output ( of Siren? )