Hello
I’m in the process of fitting a Stebel airhorn to my NC. Can anyone recommend the best place to take the 12v feed from (I’m using a relay).
Thanks in advance.
Dave
I have always taken the main feed direct from the battery post and used an in-line fuse to protect it. Use a decent thickness of wire as it does draw a big current to start the pump. The original live can then be used to trigger the relay.
You could use one of these. http://www.amazon.co.uk/Add-A-Circuit-Fuse-Holder-Standard-20amp/dp/1550063146
It would then have it’s own dedicated circuit. I used one last week to install heated seats in a mk2.
PS. They’re also available from ebay with whatever fuse rating you need.
Hi,
I also have Stebel horn waiting (for better weather) in the garage to be fitted,
Anyone know what needs to removed to get at the old horns and fit the new one as
I believe the old ones are either side of the radiator behind the front bumper.
I got this type of fuse unit to feed the horn and anything else that may need a feed later on.
Ned
Dave - which year/model of MX5 do you have? If it’s an NB (registered between 2001 to 2005) then I can save you a fair amount of effort, as that model has air con fusing and wiring in place which can be adapted for most of the wiring you need for an air horn. Might also be true for later cars, but I don’t have any information regarding wiring on them.
Posted by Ned1:-
Hi,
I also have Stebel horn waiting (for better weather) in the garage to be fitted,
Anyone know what needs to removed to get at the old horns and fit the new one as
I believe the old ones are either side of the radiator behind the front bumper.
I got this type of fuse unit to feed the horn and anything else that may need a feed later on.
Ned
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I fitted twin electro-magnetic Fiamms to my 2012 NC2 last year. Yes, the original horns are behind the bumper, mounted either side of the radiator. “Officially” the bumper needs to come off but I managed to sort mine by running the front wheels up onto some concrete slabs (to give a bit more working space) then dropping the front of the plastic undertray & the liners at the front of each wheelarch. That (just) gave enough room to get my hands up to the old horns, remove them & then connect & mount the new ones. Huge improvement!
Hi, Ned. I fitted the horn this morning. I decided to take the bumper off as I as I had a lot if difficulty trying to get the fog lamps in with it on. It’s a little tricky to remove but much easier fitting the horn with it out the way. I replaced the passenger side horn with the Stebel and left the other in place.
Gerryn, its an NC - without A/C. The wiring may be there so I’ll take a look. As suggested by Mad Malc I’ve just wired it directly to the battery for the time being whilst I decide what to do.
Please don’t use piggy back fuze holders as shown above as the circuit you plug into might already be near the limit of the fuze already fitted and by adding extra load you could overload your fuze box take a fuze feed directly from the battery oh and before someone contradicts me I’m an auto electrician by day with 20 yrs experience
I’m a bit confused here - Dave said he has air horns, but has apparently connected them on the existing wiring (replaced an OEM horn with a Steibel). Any air horn requires a compressor, which can take 20 amps, so connecting one to the existing wiring has two hiccups - 1) it won’t work without a compressor, and 2) there is no means of making an electrical connection to an air horn, it needs an air feed from the compressor.
As the existing fuse is a 20 amp one, then if the horn fitted is also electric (not an air horn) there shouldn’t be a problem.
One the other hand, if it is an air horn, then the loading on the 20 amp fuse has been increased, as the compressor still needs close to 20 amp and the existing OEM horn needs around 10 amp - total load of up to 30 amp in my estimation. Not good.
Right - I first fitted air horns to an MGB (way back when) and disconnected the OEM horn. Bad decision! I stopped at traffic lights one day in Nottingham, and the lights were changing (amber on)) when a family group - with children, decided to cross over. I pressed the horn button, and they all nearly jumped out of their skins. The mother mouthed off at me, and the husband shook a clenched fist, and for a minute I thought I was in for it. I was trying to warn them that they were asking for trouble - traffic was already moving forward coming the other way, but they carried on across the road and everyone had to stop suddenly while they complete their manoeuvre.
So - when I got back home I rewired the air hons to a separate circuit, with a separate switch and reconnected the OEM horns to the steering wheel ring switch. THat way I had two working horns, one for town use, and one for country driving. Never had any more fist waving after that. Did the same when I fitted air horns to the Five.
So Dave - are they air horns or electro/magnetic ones?
I was told that from about 2000 Mazda would be fitting all wiring (no matter what fitted options there were) so options could be added as and when required, which is why the Mk2.5 has fuse and wiring already in place for air con, all I needed to do was pick that up for the supply, fit a relay, and run a single wire back to the cabin so I could fit a spring loaded long lever switch where it was convenient. That switch wire is connected, via the switch to Chassis. - Other (engine side) fitted relay coil connected to fuse feed. This is standard for Mazda, all items are pos fed, and turned on by connecting return to neg.
Note - connecting directly to battery - always put the fuse adjacent to the battery, if you don’t, then there’s a chance of a car fire. A feed taken directly from the battery, but fused up forward anywhere means the bit of wire between battery and fuse can in some circumstances short to earth (chassis) and you could experience a fire as there’s no fuse protection between the short and the battery. Battery is (OEM) 32 amp, so the wire can rapidly overheat and cause more problems than you can imagine. Don’t go there!
Ned on the Mk3 you need to remove the engine undertray and without a two post ramp it is a pig to do as there are nuts to get off that are hard to get to and you need a lot of room underneath the get the undertray off.
One of the guys traveled an hour from home to get to my two post and said he was glad he did.
Gerryn - it’s an airhorn - Stebel compact (the compressor and horn is all one unit). I’ve got it wired up to a relay that came with the horn, I’ve removed one of the OEM horns and I’m using the feed from that to switch the relay. Just trying to figure out where the best place is to take the feed for the airhorn. I see what you’re saying about wiring direct to the battery, I’ll see if I can find the A/C wiring and tap into that.
Leaving one of the original horns in place works quite well - a quick tap on the horn just sounds the OEM one as there is a delay on the Stebel, leaning on it for longer gives the full effect,
Ned/Drumtochty - no need to remove he undertray. Just took the bumper off.
Dave -
I don’t know if it helps or not, but the aircon live connection is on the nearside of my car, on a buttress which I imagine is where the aircon unit fits. This is located in the front nearside corner of the engine compartment, and immediately before the air intake hole in the wheel well.There’s two plugs, one is for the live connection, and the other goes to the offside of the car for the aircon clutch (electric operated) Not sure that quoting wire colours will help, as they could be different to mine (often are, between Mk’s I’ve found) If you’ve got a multi-meter, or even a test probe or light with leads, then try each terminal in the plug and see which one is live. You could also - before you start searching for this - check if there is a fuse in the aircon fuse socket in the main box under the dash, if it’s there, then hopefully the wiring is as well, should be a 20 amp fuse. Read between plug and chassis (with the check device)
I see what you mean about delays, if it stays like that then you’ve accomplished both my points!
As I’ve posted elsewhere I’m taking delivery of an NC in 10 days time, and I’m trying to get the necessary mods over with asap…
An auto electrician will be fitting the dash cam on the first day of ownership (Sods law rules)together with a Steibel Compact, is there anything else electrical that needs doing at the same time?
Obvious reply - what you got in mind? Getting stuff not bought, but intended could mean getting any wiring additions or mods done in advance will save time later, but I can’t suggest what you might need to cater for - only you can. Sorry. Any such additions should be left unconnected at both ends, final connection made when objects are in place, that way the wiring is safe. Helps to tape up the loose ends as well, in case they happen to touch a live circuit or foul a moving object (like a fan or drive belt). Browse a catalogue (MX5 Parts do a good one) and see what turns you on!
Something else came up today, while chasing a connection for a powered antenna. All NA’s do not have wiring in for optional extras, only NB’s did. Apparently (I’m told by a respected source) Mazda’s intention with regard to optional extras on NA’s was “If you want an extra, then the dealers can fit it”, and obviously - will charge for it.
Do NC’s and ND’s follow the new principle? I don’t know, sorry, I didn’t ask. I know (from Robbie) that the NC is part Can bus, but only between major components, which I assume is main modules (those little black boxes which no-one understands!)
What’s Can bus? One of several bus systems. If you have a computer then it’s like any peripheral that plugs into a USB socket. Take the keyboard for example on a desktop Computer.
In simplistic terms, a major reduction in wiring between components, simplified assy and production costs. If Can bus becomes a major issue (it already is with some manufacturers), then every component will work more like a computer than an electrical wired system. Each working component may have two circuit connections, a Can bus connection and a power line if needed, - lighting for example. If something goes wrong, then like modern TV’s, you don’t fix it - you replace it. Welcome to the modern world - - - - - Enjoy your electric mods while you can, days are flying by.
Anyone ever look under the bonnet of a 1930’s Austin 7 ? Even post war vehicles were simple. A mechanic was a mechanic, nowadays they are Technicians. Tomorrow they will be diagnostic technicians. They may still need a mechanic, lurking in the grease pit, unless they start swapping engines and drive trains to something else (electric motors.) Bye Bye engine builders and mechanics. For anyone starting out in working life, then I’d recommend becoming an electronics engineer, if we have to perform well under Brexit, then that’s the way to go, here or anywhere in this future world. Specialisation is the key word. And no - I haven’t forgotten agriculture either, that’s another field. America needed cotton pickers, we need spudbashers too - - - -
Sorry, I could have phrased it a whole lot better…
In the past I’ve found that on any vehicle I’ve bought there are certain things that need addressing on that particular model as a matter of course - on my Honda ST1300 motorcycle it’s the particularly weedy horn (I have a Stebel compact on there too), the screen, and the saddle… all items which the high majority of riders have replaced. There are of course a multitude of other customisable parts as well, but those are the most common.
From trawling through the forums it appears that the horn is also a perceived weakness on the MX-5 so I have one on order, but wondered if anyone could offer further suggestions to save possible problems in the future.
My intended immediate list includes the horn, replacing standard bulbs with LED’s wherever possible, and getting the chassis and other bits protected with underseal or similar. I specifically mentioned electrics as it’s off to the Auto-electrian on day 1 for a dash cam fiting, so if there was anything electrical it would make sense to do it on the same day.
Hi Steve,
I have fitted air horns to our Mk4. I used the original feed to the old horns to activate the relay. A simple extension of the wire is easy. I took the opportunity to bridge the two horns and put in an extra wire so I can restore the original horns quickly and easily. On the Mk4 the two horns have separate feeds, hence the bridge. One of the original feeds is now not in use.
I took the main new horn feed direct from the battery with an inline 30amp fuse in place as close as possible to the battery connection. It is important to use the size of wire recommended in the instructions to your particular horn as they do pull very hard on the wire to get the pump spinning.
This method is the safest as it keeps all the new high load completely separate and isolated from the original wiring. The original feed wire is more than capable of switching the relay.
If you need any more info just ask.
I recently fitted one of those exact same fuse boxes to my Liege trials car as part of it’s conversion from an engine with a dizzy and carb to one with a dedicated ECS, fuel injection and electronic ignition (and supercharger).
They work well, but there are some potential safety issues to be aware of.
One has already been made, about the unprotected length of live wire leading from the battery to the box. An inline “main” fuse would be a good thing, before the fuse box
Secondly, the “input” live post is bare. It needs an insulating cover of some sort for safety. I fitted a 20mm length of rubber tubing held on by a tie-wrap.
Thirdly, although it might be obvious to most, don’t be tempted to fit “spare” fuses in the box. This makes the bare output terminals live.