I'm a bit confused as to how the horn ring functions in my 2014 Police Interceptor Utility. The upfitter manual says that there is a ground loop taped up under the instrument panel cluster for use. Does this mean I have to use my own relay if I want to utilize the horn ring to control a siren with the horn ring then functioning as a switched ground of my own relay?
Police Interceptor Utility Horn Ring
- Thread starter billyfromhill
- Start date
It depends on the siren unit you're using and if you want the regular horn to be disabled. On some sirens, like the Smart Siren, you just cut the loop and run both wires to the siren unit. It will have an input and output. These types automatically disable the vehicles horn.
Others, like the Storm Pro, only have a horn ring input. You don't have to use a relay but I always do because it prevents the vehicle horn from going off when the siren is activated and the siren horn from going off when the siren is off. It's up to you but I recommend using a 5 wire relay.
For the first option or the relay option you'll need either a multi-meter or a test light, after you cut the wire loop, to check for ground when the horn button is depressed on the steering wheel. That wire will go to the horn ring input or to pin 30 if using a relay. The other wire will go to the horn ring output or pin 87a on the relay. That's all for the first option but for the relay you'll wire pin 87 to the horn ring input on the siren. Pin 85 will go to ground. Pin 86 will go to a switch, either separate or one on the controller. Another alternative it is wire pin 86 to one of the outputs of the slide switch, so it automatically turns the relay on and off with the lights.
Others, like the Storm Pro, only have a horn ring input. You don't have to use a relay but I always do because it prevents the vehicle horn from going off when the siren is activated and the siren horn from going off when the siren is off. It's up to you but I recommend using a 5 wire relay.
For the first option or the relay option you'll need either a multi-meter or a test light, after you cut the wire loop, to check for ground when the horn button is depressed on the steering wheel. That wire will go to the horn ring input or to pin 30 if using a relay. The other wire will go to the horn ring output or pin 87a on the relay. That's all for the first option but for the relay you'll wire pin 87 to the horn ring input on the siren. Pin 85 will go to ground. Pin 86 will go to a switch, either separate or one on the controller. Another alternative it is wire pin 86 to one of the outputs of the slide switch, so it automatically turns the relay on and off with the lights.
I was thinking of connecting the cut wire to pin 85 and connecting pin 86 to a 12V hot wire from my fuse block. That way when I press the horn ring the relay closes between pin 30 and 87.
My understanding is that the ground loop taped up in the I/P tunnel is always hot. If I cut it I will have one half that is always hot (which I would cap off and not use) and the other half which connects to ground while the horn ring is depressed. Is this correct? I don't see why you would connect the cut wire to pin 30.
My understanding is that the ground loop taped up in the I/P tunnel is always hot. If I cut it I will have one half that is always hot (which I would cap off and not use) and the other half which connects to ground while the horn ring is depressed. Is this correct? I don't see why you would connect the cut wire to pin 30.
By wiring it up to the relay in the way I've stated it allows for use of the factory horn still. If you have no desire to use the factory horn then simply cap that wire off and wire the horn directly to the siren unit's horn ring input, providing it will accept the grounded signal. If it requires a 12V signal instead of ground then you will need to wire in a relay as you stated above. Otherwise the relay isn't needed.
I want to connect the Horn Ring to the airhorn switch of a FedSig MS4000U siren. The stock horn will only work when the vehicle is off.