Printer Friendly Forum Posts - viper 5000 accessory line addition

I have a 2006 Scion tC with a Viper 5000 alarm installed.
Vehicle Diagram:https://www.the12volt.com/installbay/forum_posts.asp~TID~59369

I am going to install a train horn in a couple of weeks. I want two things: to tie the train horn sound circuit into the stock horn with a switch so I can either sound the stock horn, or both horns.

The second thing I want is to wire the train horn sound circuit into an accessory port of my alarm so I can remotely activate it if want to.

A few details:
The scion stock horn is a (-) triggered circuit as described above.
The accessory port on the viper outputs a 200 mA (-) current.

Will this work:

Using a SPDT Relay (no diode in it), I would:

Pole 85= Put a 12v Constant fused at 5 Amps

Pole 86= Put two wires: Tap a wire from the stock horn circuit to here with a switch inbetween to control activity.
Second wire: Put the alarms 200 mA (-) accesory line here.

Pole 87=Line to Solenoid of train horn.

Pole 87a= Not used, insulate from being exposed.

Pole 30=12v Constant fused at 5A

If that doesnt work, please give me some constructive criticism.
BTW, if you are wondering why I want a train horn, Ive been hit 3 times this past year in my car by SUVs who didnt see or hear me and merged into my car...