stevodevo
Member
Hi All,
I've bought myself an upgrade to the "RoadRunner meep meep" stock horn for my 2012 D22. I thought this might be a good little project to educate myself a little bit about auto electrics. I'm struggling a little bit, and hope someone can help push me in the right direction? I read through all the related threads on this forum - including the ones that "just work" on the existing wiring - but I haven't found anything that seems to fit for me.
The replacement horn I bought is a Stebel Nautilus Compact. Seems to be a popular choice, and I agree it sounds really nice. The label says it's 12V less than 18A. It comes with one 12V 20A 4 pin relay.
In my Nav, I have on the horn circuit a 10A fuse, a 3 pin 12V 15A relay, with 3 wires (green, red and white) coming out of the bottom of the relay. The standard horn has a single [quite thin] red wire connecting to the horn itself, and I presume the horn is grounding itself through the connecting bracket that bolts onto the chassis.
Just for sh!ts 'n' giggles I tried just connecting the red lead to the new horn and added another ground lead to the negative terminal on the horn, and it works. Plenty loud and good tone, with no sign of it not getting enough juice. However... it keeps blowing the 10A fuses after a couple of short toots.
The diagram that came with the new horn says the cable connecting to the horn should be 2.5 mm2 (relay terminal 87). I'm a bit curious why it has a "squared" symbol on a round cable? Or maybe I'm jumping to conclusions and it doesn't relate to cable thickness at all?
It doesn't specify any cable thickness for connecting to the the power source, but does show a 20A inline fuse (relay terminal 30). It specifies 1 mm2 for the cable connecting to the horn button (relay terminal 86). It doesn't specify any cable thickness for the earth cable (relay terminal 85).
All of the current red, green and white cables are about 1 mm thick, including the red cable connecting to the horn.
I don't really "get" what relay amperage means (although I do get what purpose they serve), but if I hazard a guess I think it might mean that it will allow 15A of current to flow through the switch if the connecting device demands it. Or does it mean it can only handle 15A, and any more demand will break it - or is it neither of those? The new horn only specifies "less than 18A", so assuming it's pulling 15-18A, that's why I keep blowing 10A fuses.
I think I understand correctly that I need to upgrade the cabling or I'll risk the cables themselves turning into fuse wire and burning through, although I'm a bit curious as to why there's no specification for the cable connecting to the power source.
So I suppose, long story short, what would be the likely outcome if I simply upgraded the cable running to the horn, and swapped the standard 10A fuse for a 20A? That would seem like a nice easy job, because it's easy to see where that cable needs to go... I'm not so sure about the cable connecting back to the fuse and power supply.
The above is as much a question about whether it would be an acceptable shortcut to installing the supplied 4 pin relay, as understanding "why" it wouldn't work i.e. I'll blow a relay, or I'll melt the power source cable etc.
To be honest I'd like it if the above scenario would work safely, because it's still a relatively new car, and I don't want to go modifying too much while it's still under warranty. Call me vein, but I just can't put up with my wife's Barina Spark, having a WAY more masculine horn than my big black Nav!
Thanks for all who managed to read this far down, and thanks in advance for any advice offered. Next project will most likely be some extra speakers in the back.
Thanks,
Steve
I've bought myself an upgrade to the "RoadRunner meep meep" stock horn for my 2012 D22. I thought this might be a good little project to educate myself a little bit about auto electrics. I'm struggling a little bit, and hope someone can help push me in the right direction? I read through all the related threads on this forum - including the ones that "just work" on the existing wiring - but I haven't found anything that seems to fit for me.
The replacement horn I bought is a Stebel Nautilus Compact. Seems to be a popular choice, and I agree it sounds really nice. The label says it's 12V less than 18A. It comes with one 12V 20A 4 pin relay.
In my Nav, I have on the horn circuit a 10A fuse, a 3 pin 12V 15A relay, with 3 wires (green, red and white) coming out of the bottom of the relay. The standard horn has a single [quite thin] red wire connecting to the horn itself, and I presume the horn is grounding itself through the connecting bracket that bolts onto the chassis.
Just for sh!ts 'n' giggles I tried just connecting the red lead to the new horn and added another ground lead to the negative terminal on the horn, and it works. Plenty loud and good tone, with no sign of it not getting enough juice. However... it keeps blowing the 10A fuses after a couple of short toots.
The diagram that came with the new horn says the cable connecting to the horn should be 2.5 mm2 (relay terminal 87). I'm a bit curious why it has a "squared" symbol on a round cable? Or maybe I'm jumping to conclusions and it doesn't relate to cable thickness at all?
It doesn't specify any cable thickness for connecting to the the power source, but does show a 20A inline fuse (relay terminal 30). It specifies 1 mm2 for the cable connecting to the horn button (relay terminal 86). It doesn't specify any cable thickness for the earth cable (relay terminal 85).
All of the current red, green and white cables are about 1 mm thick, including the red cable connecting to the horn.
I don't really "get" what relay amperage means (although I do get what purpose they serve), but if I hazard a guess I think it might mean that it will allow 15A of current to flow through the switch if the connecting device demands it. Or does it mean it can only handle 15A, and any more demand will break it - or is it neither of those? The new horn only specifies "less than 18A", so assuming it's pulling 15-18A, that's why I keep blowing 10A fuses.
I think I understand correctly that I need to upgrade the cabling or I'll risk the cables themselves turning into fuse wire and burning through, although I'm a bit curious as to why there's no specification for the cable connecting to the power source.
So I suppose, long story short, what would be the likely outcome if I simply upgraded the cable running to the horn, and swapped the standard 10A fuse for a 20A? That would seem like a nice easy job, because it's easy to see where that cable needs to go... I'm not so sure about the cable connecting back to the fuse and power supply.
The above is as much a question about whether it would be an acceptable shortcut to installing the supplied 4 pin relay, as understanding "why" it wouldn't work i.e. I'll blow a relay, or I'll melt the power source cable etc.
To be honest I'd like it if the above scenario would work safely, because it's still a relatively new car, and I don't want to go modifying too much while it's still under warranty. Call me vein, but I just can't put up with my wife's Barina Spark, having a WAY more masculine horn than my big black Nav!
Thanks for all who managed to read this far down, and thanks in advance for any advice offered. Next project will most likely be some extra speakers in the back.
Thanks,
Steve
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