7
Wire the relay posts
This relay is very similar to the 4-pin relays we use with some of our kits. The added post ‘87A’ is used for a second accessory. These relays are designed to switch between two circuits, when on or off. You will set this up so that one circuit is for the regular stock horn and the other is for the train horns. Both can be honked with the steering wheel, but only one at a time will honk.
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87: Connect the red wire from our solenoid valve to this terminal.
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87A: Connect the wire from OEM horn (the short wire lead we cut earlier FROM the horn itself. Route this to pin 87A).
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30: Connect this terminal to the side of the OEM horn wire that comes from the steering wheel (the wire that is NOT coming off the horn itself).
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86: Connect this post to the wire used for the upfitter switch. It doesn’t matter which upfitter switch you use, just that you use one.
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85: Route this post to the frame of the vehicle as a ground.
The steering wheel will be used to honk each horn, and the upfitter switch allows you to switch between the two. When the vehicle is off, the train horns will not honk, as the upfitter switches are key-power on.