Hi all,

About 6 months ago I wired in some E series falcon horns. They were soldered to the factory horn single wire (green w/black trace). They worked fine with short beeps, but when I held the horn down for a good 10 seconds (someone was a real fool on the roads) the horn died.

I did some serious investigative work, I resorted to checking all fuses and found that the No.12 fuse in the engine bay fusebox is blown. It is labelled in the manual as "ECU & Horn".

To avoid having to contentiously replace that fuse, I was thinking to increase the fuse from the factory 10A to a 15A to allow for,what appears to be an extra power drain, from the 2x falcon horns. My concern is because it's listed as being apart of the ECU circuit.
If I was to put a 15A fuse, I'm wondering if I risk the ECU having a circuit fault or overloaded with power?
Should I not worry about the ecu part and upgrade the fuse?
Or better yet, is there any way I can prevent the fuse from blowing the first place? Wire the horns to get power from somewhere else? If I was to do that, then I'd need to wire in some sort of relay/transistor as a remote trigger. Circuit suggestions?

Appreciate any and every help!
Lecky techy genuis' most welcome!

Thanks heaps.

I wouldn't up the amp on the fuse, it may cause the wiring to melt due to the fuse not blowing. If the horn doesn't run a relay I would be installing one and its very easy to do.

I wouldn't up the amp on the fuse, it may cause the wiring to melt due to the fuse not blowing. If the horn doesn't run a relay I would be installing one and its very easy to do.

Thanks.

That is a concern for sure. I was just thinking that allowing 5 more amps through can't do much damage.

The factory horn circuit itself runs a relay in the engine fuse box but the extra circuit I've tapped in does not. I've just stripped back the factory horn wire and tapped the new horn power wire onto that.
I'm thinking of running external constant 12v power straight to the two horns and then having the relay to use as a remote switch.
That should work?

Yeah that will work. Do the horn use a postive or negative trigger wire?

Yeah that will work. Do the horn use a postive or negative trigger wire?

Brilliant!

I believe the factory horn is a positive trigger wire. Not sure how to test it though. Testing with a mutlimeter returned a 12v+ reading when the horn was pushed down.

I'm guessing a standard relay like one in the engine bay fuse box will suffice fine?

The horns are drawing too much current and the wire can't cope so it blows the fuse. I think the easiest way would be to use another relay and decent sized wire from battery to relay (fused link), relay to horns, relay to earth and earths on the horns.

What he above said. A relay that switches on directly from a power source (battery).

Thanks guys!!

I'll definitely look into wiring in a relay into the circuit.

As far as sourcing power goes, couldn't I just tap into anouther 12v circuit that has can take a higher current (e.g something with a 15A or 20A fuse) ? Running off the battery would mean anouther extra connector on the terminal. That area is already tight with a 4ga audio cable clipping on the positive terminal. Not to mention the difficulty with getting wires from the battery across the top of the condenser to the other side where the factory horn is. I'll need to take off the front parts for that.

I was thinking of maybe tapping into the washer jet circuit (provided it can handle more than 10A current) because I physically couldn't hold the horn, drive and use the washer jets at the same time.

How long is the ground wire?
How well is it grounded?
Where did you install your Horns?