Horn probles

[oworm]

I made a short video to ask about a horn problem. There are three horns on this truck but only oe has ever worked directly from the relay. The other two will work from a direct feed from the battery but not from the relay. Any idea why that would be? Electric are not my strong point BTW
http://youtu.be/y_3VznA1bFg

 

[79jasper]

If they're on separate relays, it's the relay.
If they're on the same, they're not getting enough power........

Either do separate relays, or one big one with bigger wire to it. Like 6 maybe.
Some horns will really pull some amps.

 

[oworm]

If they're on separate relays, it's the relay.
If they're on the same, they're not getting enough power........

Either do separate relays, or one big one with bigger wire to it. Like 6 maybe.
Some horns will really pull some amps.

I cant understand why the present relay wouldn't be enough since it has three outputs. You could have a point with the amperage though.

 

[79jasper]

What's the power in wire look like? (Size)

 

[gandalf]

I cant understand why the present relay wouldn't be enough since it has three outputs. You could have a point with the amperage though.

I just hit the wrong key and deleted my answer, so I've got to start over.

You've got me confused, so I have several questions. This is on an '84 truck? Where is the relay located? Is it a normal 4 post relay? Your statement about 3 outputs is what has me confused.

I'll try to explain, from my limited understanding of auto electrics. Your standard relay has 4 posts, numbered 30, 85, 86, 87.

I'll use my electric fuel pump relay as an example. I think I have this right, reading from my own notes.

30 is a fused connection directly from the battery, or some other constant hot source.

87 goes directly to the electric fuel pump.

86 is the trigger, in this case coming from the FSS on the IP. That trigger wire has power only when the ignition is on.

85 goes to ground.

So, you turn on the ignition to start the truck, and post 86 receives power, and allows the power coming in on post 30 to leave the relay on post 87, in this case turning on the electric fuel pump. The power coming in on 86 from the FSS allows power to go out on 87.

When I turn off the ignition, that kills power to the FSS, which in turn kills power to the relay, which in turn kills power to the electric fuel pump.

That's about as clear as mud, isn't it. At any rate, that's my story, and I'm sticking to it. The end result is that my fuel pump works.

 

[oworm]

I just hit the wrong key and deleted my answer, so I've got to start over.

You've got me confused, so I have several questions. This is on an '84 truck? Where is the relay located? Is it a normal 4 post relay? Your statement about 3 outputs is what has me confused.

I'll try to explain, from my limited understanding of auto electrics. Your standard relay has 4 posts, numbered 30, 85, 86, 87.

I'll use my electric fuel pump relay as an example. I think I have this right, reading from my own notes.

30 is a fused connection directly from the battery, or some other constant hot source.

87 goes directly to the electric fuel pump.

86 is the trigger, in this case coming from the FSS on the IP. That trigger wire has power only when the ignition is on.

85 goes to ground.

So, you turn on the ignition to start the truck, and post 86 receives power, and allows the power coming in on post 30 to leave the relay on post 87, in this case turning on the electric fuel pump. The power coming in on 86 from the FSS allows power to go out on 87.

When I turn off the ignition, that kills power to the FSS, which in turn kills power to the relay, which in turn kills power to the electric fuel pump.

That's about as clear as mud, isn't it. At any rate, that's my story, and I'm sticking to it. The end result is that my fuel pump works.

Did you watch the video?

 

[gandalf]

Did you watch the video?

Yes, but I missed the part where you pointed to the relay. Is that a normal Ford relay? I don't recall seeing one right there before, though I could be wrong.

Questions again. When you try to run all three horns, do you have them connected to a single connection on the relay? How many connections point are there on that relay? Are they numbered?

Using a multimeter or a test light, have you verified what each connection point does? Constant hot, trigger,...

Have you checked continuity on all wires?

Assuming that everything is wired correctly, can you feel the two non-stock horns vibrate when the stock horn blows?

There's always the possibility that the relay just can't supply enough power for all three horns.

We're getting about to the limits of my knowledge on auto electrics. In addition, my wife is calling to take her out somewhere, so I'll be gone for a spell.