Dear all, I need your electrical expertise on fuse.

[Lester]

Dear all

 

 

I've installed a set of air horns on my vehicle. After a few horn sounding, there was no more sound. I think I might have blown the fuse. Question:

 

My stock horns require an amperage of 10A, (see attachment) in the fuse box is a 10A fuse for the stock horns(a pair). I looked at the box for the air horn and it requires a 20A fuse. When I installed the air horn, I left one side of the stock horn back on, connected. When I did the connection, I spliced one of the pair, and just connected the positive and negative sides to the air horn, with out the relay which is included in the air horn box. Cos in my circuit diagram, you can see an existing relay.

 

Should I use back a 10A fuse,

change to a 20A fuse and take out the stock horn,

or use a 20A fuse and keep both the stock horn and air horns on?

 

In the Western part of Singapore, where is a good choice to get fuses on a Saturday? Or do I have to go down to Sim Lim Tower? Your help will be appreciated. Thank you in advance.

 

 

Lester

[Pauly75ts]

Hi! there, Lester,

 

Electricals that has a switch needs a relay, to prevent damage to the switch, i.e. the horn button. You can look for fuses at Pioneer Road North, there're a few w/shops & electrical shops there.

 

Rgds

 

Paul Yong

[Lester]

Hi Paul

 

Thanks for your prompt reply. But since my stock circuitry has a relay, do I need the one that came with the air horn box? ie to say, if my stock relay is for a 10A fuse, can I pluck in a 20A fuse into this stock relay? Or do I have to use the 20A fuse with the relay in the box that says 12V 30A together with my stock relay?

 

 

Lester

[Pauly75ts]

Hi! there, Lester,

 

I don't know much about electricals, other than what I've learnt from friends & my wireman. You'd have to ask an electrician about the use of the 20A fuse to a wiring for 10A fuse.

 

Rgds

 

Paul Yong

[Cool]

LEster,

 

If your stock fuse is 10A, then you canno replace it with a 20A cos it might fry your cables..

 

Maybe you would like to revert back to old horns until TB comes back from Japan.. he would be more knowledgable to advise you

 

My simple 2 cents worth.

[Yongwd]

direct plug and play. no rewiring required.

 

the relay that comes with the horn indicates max 30A load, it does not mean that the horn draws that amount of load.

 

Try with 10A fuse, no harm with that. I seldom see car horns require more than a 15A fuse.

[Lester]

Dear all

 

I've put in a 20A fuse into my stock relay. I figured since the horn is not activated long timings like the lights, so should be ok for the wiring and the stock relay. Let's see wat happens. I've tried holding onto my horn button for 15 secs and touched the wiring after that. Seems fine. No heating up. How often do you sound yoru horns for more than 15 secs? Now it's just the air horn and no more stock horn on the other side. Since the air horn box indicated a 20A fuse, I tried a 20A. Anyway like wat Shagmobil said is true. The indication does not equal to the output drawn. Here's a pic that shows one side of the pair. Sorry it's not very clear and obvious. I cannot make things like that too obvious can I? Maybe you guys can take a look when we next meet up. Thank you for all your help, Paul, Cool and Shagmobil. Really appreciate it!

 

 

Lester

Edited June 2, 2002 by Lester

[BoneStock]

Dear all

 

I've put in a 20A fuse into my stock relay. I figured since the horn is not activated long timings like the lights, so should be ok for the wiring and the stock relay. Let's see wat happens. I've tried holding onto my horn button for 15 secs and touched the wiring after that. Seems fine. No heating up. How often do you sound yoru horns for more than 15 secs? Now it's just the air horn and no more stock horn on the other side. Since the air horn box indicated a 20A fuse, I tried a 20A. Anyway like wat Shagmobil said is true. The indication does not equal to the output drawn. Here's a pic that shows one side of the pair. Sorry it's not very clear and obvious. I cannot make things like that too obvious can I? Maybe you guys can take a look when we next meet up. Thank you for all your help, Paul, Cool and Shagmobil. Really appreciate it!

 

 

Lester

 

Hi Lester,

 

Just thought I'll add my 2 cents. If you change to horns with higher rating...theoretically, you've to replace the following:

 

1) Cables - as mentioned by Cool...as prolonged usage will fry the cables.

2) Fuse - if not the stock ones will blow.

3) relay - got to replace this as well 'cos relays also com with current rating.

 

It's not advisable to mix the old horns with the new ones. If you must do that, suggest that you maintain 2 separate circuitries....i.e. 2 fuses, 2 relays and 2 set of cables of different current ratings.

 

HTH

[Eric]

Fuses are generally there for your safety and the safety of your equipment. The idea is that the fuse should blow before you damage any other equipment (like your cables, etc. as mentioned earlier).

 

When you change to higher rated fuse, you should ask yourself if you think your cables can take that amount of current (20A in your current case)?

 

Shag is right. If the spec mentions a 20A fuse, it means that it won't draw that amount in normal usage. No one will spec a fuse that keeps on blowing. Unless you have great confidence in your cables, you may want to stick with the 10A fuse. That way, you can be sure that the fuse will blow before your cables melt (like if there is a short circuit).

 

It's good that you only have 1 set of horns connected. Connecting stuff in parallel will increase the amount of current needed. If your old horns use 6A and your new horns use 6A, they will draw 12A when connected in parallel.