Technical MY HOOOORRRNNNN :'( Fuse has gone again -.-

[LeakingLava]

Well, I honestly thought that the thread that I posted was over. Here I am again. I decided that I should make a new thread as the other one could be too long winded. Here's the previous thread anyway.

Basically, I installed an air horn. I had run a 12v from the original horn wiring into a relay which had a 12v main from the battery and then straight into the compressor.

My problem is that the original horn's fuse blows when the horn is blown for about 1-2seconds. If it's only some miliseconds, it doesn't blow but if I use the horn a few times for 1-2 seconds as said, the fuse blows. It's a 15A fuse in the fusebox.

 

[Ziggy122]

What fuse is recommended by the horn manufacture?

Because if the horns use 18amps, they'll need a 20amp fuse

Obvs a 15amp will blow

as for your wiring method, have you wired the new horn to a new relay setup?

ziggy

 

[LeakingLava]

What fuse is recommended by the horn manufacture?

Because if the horns use 18amps, they'll need a 20amp fuse

Obvs a 15amp will blow

as for your wiring method, have you wired the new horn to a new relay setup?

ziggy

In the manual, it said 15A and the first one that I blew a few days ago was 15A. Yes I have. I did what you recommended in my other thread which was to take the 12v low current side from the original horn so that I can use the original horn with the new setup.

In the new relay setup, I have a 20A fuse on the line from the battery into the main 12v of the new relay. That doesn't blow.

The only problem as I can see is the low current side of the new relay. Maybe it could be drawing too much current?

 

[fingers99]

Not sure how you've done (after all that).

I'd splice into the +ive feed for the original horn (after the original relay) and use that as the +ive feed for the new relay.

Unless there's a lot more current going through the original fuse, ir shouldn't blow.

 

[Ziggy122]

Without se'ing a wiring setup of how you've wired it up - im baffled as to whats what

When i wired my TM's up

I used the current Stock horns wiring - took a +ve feed from that and used that to trigger the low current side of a seperate relay to power my more hungry horns

ziggy

 

[LeakingLava]

Without se'ing a wiring setup of how you've wired it up - im baffled as to whats what

When i wired my TM's up

I used the current Stock horns wiring - took a +ve feed from that and used that to trigger the low current side of a seperate relay to power my more hungry horns

ziggy

Sorry guys. Could just be my english. As far as I understand, I've done exactly the same as what you've done Zig. Again, sorry.


Oh, there's a 20A fuse on the line from the battery to the relay.

 

[Ziggy122]

Hmmmmm

You havent got the Relay low current side using the same +ve and -ve wires as the actual horn?

Personally
I prefer to earth the relay via a different earth, or direct to battery negative

Ziggy

 

[atom0007]

is the old horn still wired up then and blowing at the same time as the new horn?

 

[LeakingLava]

Hmmmmm

You havent got the Relay low current side using the same +ve and -ve wires as the actual horn?

Personally
I prefer to earth the relay via a different earth, or direct to battery negative

Ziggy

Ermm, I do have the low current side of the relay using the + and - wires of the original horn.

I understand that but, would that make a difference that's enough to make the new relay's low current side to draw more current which blows the original fuse? As seen in this wiring that I found somewhere online, I don't see how the earth could be the difference. Please do explain it to me as I think I'm just really confused right now.

is the old horn still wired up then and blowing at the same time as the new horn?

Yes it is but there is a tiny delay on activation as the compressor still has to 'act' and push the air through the tubes and all, and the original horn activates straight away, so yeah.

 

[LukeEssex]

Sorry guys. Could just be my english. As far as I understand, I've done exactly the same as what you've done Zig. Again, sorry.


Oh, there's a 20A fuse on the line from the battery to the relay.

nice drawing lol

 

[atom0007]

I can't see anything wrong in your wiring. The coil on your new relay should only draw a few mA, so that extra load that the Oem horn loop sees is tiny.

I haven't read your original thread.

Are you sure it's wired correctly?

It sounds more to me like you've got both horns wired in parallel, that would blow the fuse

 

[a1ant]

Hi mate,

Did you do the tests at the end of your other thread?

You need to establish how much current the original horn is pulling, and also establish how much current the LC side of your new relay is pulling. You can do this the way in which I described in the other thread.

As above the new relay LC side should only pull a few mA but you did say it was a cheap Chinese relay so you should really test it.

If your original horn is on it's way out and pulling say 13amps, and your new Chinese really is rubbish and pulling say 1-2 amps that could account for your 15amp fuse popping.

I would also remove the high current fuse from your 25amp wire And then try the horn, if BOTH horns are still working, you know you have your wiring crossed somewhere.

Technically if everything working the way it should, the way you have wired it should work fine.

Also, as has been suggested, I would give the new relay it's own earth (short bit of cable direct to mounting bolt etc) and put the original earth plug back on the oem horn.

Alan

 

[LeakingLava]

nice drawing lol

LOL Thanks. Hahaha.

I can't see anything wrong in your wiring. The coil on your new relay should only draw a few mA, so that extra load that the Oem horn loop sees is tiny.

I haven't read your original thread.

Are you sure it's wired correctly?

It sounds more to me like you've got both horns wired in parallel, that would blow the fuse

I'm positive that it's wired up correctly. I've double checked and all.

Hi mate,

Did you do the tests at the end of your other thread?

You need to establish how much current the original horn is pulling, and also establish how much current the LC side of your new relay is pulling. You can do this the way in which I described in the other thread.

As above the new relay LC side should only pull a few mA but you did say it was a cheap Chinese relay so you should really test it.

If your original horn is on it's way out and pulling say 13amps, and your new Chinese really is rubbish and pulling say 1-2 amps that could account for your 15amp fuse popping.

I would also remove the high current fuse from your 25amp wire And then try the horn, if BOTH horns are still working, you know you have your wiring crossed somewhere.

Technically if everything working the way it should, the way you have wired it should work fine.

Also, as has been suggested, I would give the new relay it's own earth (short bit of cable direct to mounting bolt etc) and put the original earth plug back on the oem horn.

Alan

Yeah I really should but again, my problem is that I don't have an ammeter to test it out. My dad had ordered one(because I pushed him to ) and I'm just waiting for it. For now, I will plug out the 25A wire. That seems to be what I really need to do.

I'll do the new relay too. I just thought that the low current side is supposed to have very low current anyway that it shouldn't matter if I do run the - into the OEM -.

The OEM plug is in the original horn btw. I used one of these things:

But yeah, I'll do as recommended.

 

[LeakingLava]

Still confused.

Did a few tests:

-Took out 25A battery-new relay wire; compressor doesn't work, original still works as usual. I think this means that the new relay is wired up correctly?

-Took out air tube from compressor so I can test for longer without the horn noise; pushed horn for about a full second maybe another half a second; fuse doesn't blow.

-Same as second; but pushed horn miliseconds at a time for about 2 seconds; fuse doesn't blow.

Didn't change the earth wiring yet as I sort of wanted to solve the problem first. Hmm, could the earth wiring be the cause of this? I don't see how that's possible but then again I could be just so confused

 

[a1ant]

Hi mate,

Yep the fact the compressor didnt run when the HC connection was removed is a good thing, means that its definitely getting its supply from the correct place and not through the original horns wiring!

To me it still looks like the two main possibilities is either the new relay itself, or the original horn. You need to test what is drawing the current to blow your fuse. Until your multimeter arrives theres not much you can do on that.

A possible test that you could do in the mean time.... is to disconnect the original horn, and leave the new relay and air-horn connected. This will take the amount the oem horn is drawing totally out of the equation, and if it still pops the fuse, you know almost certainly that you have a duff relay, or a problem with your wiring. The earthing arrangement you have at the moment should be adequate as it comes from a central earthing point, but i would still advise a separate earth just to be sure.

Alan

 

[LeakingLava]

Hi mate,

Yep the fact the compressor didnt run when the HC connection was removed is a good thing, means that its definitely getting its supply from the correct place and not through the original horns wiring!

To me it still looks like the two main possibilities is either the new relay itself, or the original horn. You need to test what is drawing the current to blow your fuse. Until your multimeter arrives theres not much you can do on that.

A possible test that you could do in the mean time.... is to disconnect the original horn, and leave the new relay and air-horn connected. This will take the amount the oem horn is drawing totally out of the equation, and if it still pops the fuse, you know almost certainly that you have a duff relay, or a problem with your wiring. The earthing arrangement you have at the moment should be adequate as it comes from a central earthing point, but i would still advise a separate earth just to be sure.

Alan

Right. Thank you, thank you. I'll take out the OEM horn and try it out for a few days. Thanks again.