wiring help...

bzzbee2 · Feb 16, 2008, 10:08 PM

I am planning on installing an air horn. the kit came with a 5 wire relay. I would like to install the horn so that it seperate from my stock horn and only activates when i press a momentary switch/button. I have searched tons of websites but have not had much luck... my understanding is that i really only need a 4 wire relay. The air pump is on the relay, the pump is controlled by a pressure switch on the air tank. if i can get some pics of everything can someone in here help me out with wiring this silly thing. The instructions that came with this are horrible...

here are my questions

1. where should the 5 wires be connected to. I understand that #30 on the relay should go to the power supply. after that its kinda a mystery.
2. the momentary switch that controls the solenoid to blow the horn... does this need to be wired through the relay? or is this run by a separate source of power.
3. purpose of the relay.. why cant i just wire the pump into a source of power that requires ignition, and wire the momentary off of a similar source? Or could i just wire the pump to the battery with a toggle switch so i could manually disconnect power to the battery to prevent a leak that may kill the battery...

Thanks

biggie5252 · Feb 17, 2008, 07:34 AM

As far as I can tell from what you wrote, this is how you'd wire it up. I'm assuming that the instructions tell you to wire the pump to a 12v source through the pressure switch to control tank pressure, and the relay/momentary switch is to actually blow the horn, correct?

bzzbee2 · Feb 17, 2008, 09:35 AM

You are correct. So i would assume that i would need to run an inline fuse to the pump. Also. what would 87a be used for?

Thanks a bunch for your diagram!!

WhiteEvo05 · Feb 17, 2008, 10:07 AM

Whether it's a four or five wire relay is not important. In your case you would just leave 87a not hooked to anything.

In a "standard" Bosch style relay, 87 is normally open (coil in the relay not energized...no power flowing across terminals 85 & 86) and 87a is normally closed (again, coil in the relay not energized)...what does this mean? When you have your momentary switch wired as in the above illustration, when you push it, the coil energizes and your relay closes the switch and your horn honks. If you were hooked up to 87a, your horn would honk all the time until you pushed your switch and then it would stop.

Make sense?

Here is a schematic of the relay, it may help you to visualize what is going on.

biggie5252 · Feb 17, 2008, 10:33 AM

Definitely run an inline fuse to the pump. Somewhere, there should be a current/amp rating for the pump. I'd get a fuse that size or the next size up.

SqEvoVIII · Feb 17, 2008, 10:39 AM

I'd have to see the instructions but
87a no connection
86 ground (trigger) I'd run the switch on a ground loop so when you press the button it sends ground to the relay.
85 and 87 should be 12v, 85 being a fused constant power for the relay and 87 being the input of what is going to be sent out to (30)
30 would go to the wire that will sound the horn.

Now this is based off a normal situation of a 12 trigger horn set up. If it requires a ground trigger then you would switch a few things. If you get stumpped scan me the instructions and I can take a look.