Horn not working

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mitchelln
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Re: Horn not working

Post by mitchelln » Tue Aug 08, 2017 9:27 pm

Bob wrote:Obvious one, I'm guessing you have the ign on, not certain if it has to be on the newer ones, but I've been caught in the past. :oops:
The wiring diagram shows it as permanently on, but I did try the ignition just in case.

The diagram shows a fuse, but goodness knows where it is. I've looked everywhere. Very frustrating.
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Re: Horn not working

Post by g8dhe » Tue Aug 08, 2017 9:28 pm

mitchelln wrote:I am looking in the drivers side fuse box. It looks like the 2L petrol has a different fuse box - less fuses than your picture for a start!
Nope the picture shows ALL the fuses that can be fitted across the range, some are options of course, it comes from the Bongo Wiring Manual site it covers all versions upto 2001 after that there are some minor variations with one fuse being moved to the fuse box located central under the bonnet;
If you hover the Mouse over the green fuse then the image will pop up to show you where the fuse is - there is a help page for all the other handy little bits as well ;-)
Image
Last edited by g8dhe on Tue Aug 08, 2017 9:31 pm, edited 1 time in total.
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Re: Horn not working

Post by Bob » Tue Aug 08, 2017 9:29 pm

I can understand that, little **gger must be hiding somewhere. :evil:
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Re: Horn not working

Post by mitchelln » Tue Aug 08, 2017 9:48 pm

Barry is a 2003. Here's the internal fusebox. No horn fuse unless it's shared. Even checked the wires going into the back. No Y/R. Checked all the fuses anyway and they're all intact.

Image

Checked the fuses under the bonnet as well. Can't see it there.

The horn has never worked since I've had it. I'm beginning to suspect that it's been messed with in the past. Perhaps to pick up permanent power for something else. If you use the wrong size Scotchlock you can end up cutting the wire leaving the power intact for the added accessory, but not the downstream original item.
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Re: Horn not working

Post by sotal » Tue Aug 08, 2017 10:50 pm

Your fusebox does look different! It even has English labels!


Your post spurred me on to have another look at mine. Mine is a 1999 diesel.

I just checked the fuse, but the fuse was fine, replaced it with another just to make sure but it was still the same.

One thing I did note though was that with the fuse in place I can hear a relay click in the dash when I press the horn. Without the fuse in I can't hear the relay - I had heard the noise before but wasn't sure if it was a relay or if it was a mechanical noise of the button moving but as it disappears without the fuse it kind of confirmed it.

So my next point to check will be to see if I'm actually getting any voltage at the horn end of the wiring (I suspect not).
If I am then I will have to check out the grounding at that point as I think it grounds just through the mount that it is attached to.

If not then I will be looking at the wiring in between the relay and the horn, and also looking for the relay itself to check out. (Does anyone know where this is?)

Sorry to jump on your thread but hoped that a similar problem may help to solve yours!
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Re: Horn not working

Post by mitchelln » Tue Aug 08, 2017 11:10 pm

Yes, the wiring diagram shows a relay. The switch in the steering wheel and clockspring wiring can't handle the surge current of the 2 horns I guess.

Worth investigating - thanks for the info!
There's no power on the Y/R wire though, which I think is the problem. That'll mean no feed power to either the relay or horns if the diagram reflects the actual wiring.

This does seem to indicate a discrepancy to the wiring diagram though. The Y/R is definitely connected to the clockspring harness on Barry, but that's not how the wiring is shown on the diagram. The other wire in the 2 pin connector (with a very OTT locking mechanism) is Y/Black, which is not on any of the diagrams! Perhaps some changes were made on the later models?

Anyway, I'll hunt for the relay tomorrow. Time for the dash to come off...

Hope the English labels on my fusebox prove useful to someone. I'll take a better shot.
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Re: Horn not working

Post by mitchelln » Thu Aug 10, 2017 8:29 am

Okay, spent an evening grubbing about in the gloom. Found out a few things the hard way ;)

The horn on the petrol is fused via the 10A hazard fuse. Kind of makes sense - it's a permanently on connection and hazards and horn kind of go together logically.

The relay (F3-03) is not behind the dash, but located under the bonnet near the front offside headlight assembly.it's
Image

In theory, the horn relay is the middle one in the front row (hence why I had the cover off to take the picture). However, all is not so simple!

It turns out the two rows of relays are reversed on the petrol. I only discovered this by taking the front relay box apart, which was no mean feat in the confined space and noticing the wire colours were all wrong. It turns out the horn relay is the middle one in the rear relay box behind.

Carefully looking at the diagram again, I could see that F3-03 relay is shown twice. Once with Japanese characters and [DE] and one with [WL-T]. It becomes apparent that DE means diesel and WL-T means petrol. So Mazda, for some completely inexplicable reason, has swapped round the two rows of relays between the petrol and diesel!! At least on the petrol they have used the same relay everywhere.

Anyway, after doing a swap of the right relay, the horns still did not work. I checked with a meter and there is power going to the coil and one switch contact and the other contact has continuity to the horns. The relay is just not actuating. So it must be either the connection from the relay to the clock spring connector, the clock spring itself or the horn switch.

If it's the clock spring, it'll probably be Mazda 6 steering wheel time as the Bongo ones seem to be very hard to get hold of. I'll have a go at plumbing in the cruise control and audio switches whilst I'm at it. Hopefully it is just the horn switch itself, so I can put that adventure off for another day ;)

So horn switch check next. I was hoping to avoid mucking about with all the airbag precautions, but will have to now.

The front middle relay on a petrol is for the AC clutch BTW ;)
Last edited by mitchelln on Thu Aug 10, 2017 8:58 am, edited 12 times in total.
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Re: Horn not working

Post by Bob » Thu Aug 10, 2017 8:36 am

Jolly useful info, and well done with th detective work. =D>
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Re: Horn not working

Post by mitchelln » Thu Aug 10, 2017 8:59 am

I feel a new factsheet coming on ;)
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Re: Horn not working

Post by Bob » Thu Aug 10, 2017 9:02 am

That would be seriously useful. =D>
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Re: Horn not working

Post by g8dhe » Thu Aug 10, 2017 9:39 am

mitchelln wrote: DE means diesel and WL-T means petrol.
You seem to be confused! The letters you refer to relate to the engine type;
WL-T is the Diesel 2.5TD version
FE-E is the 2l Petrol &
J5-DE is the 2.5l V6 Petrol

Hence your confusion as to locations of the relays etc.
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Re: Horn not working

Post by mitchelln » Thu Aug 10, 2017 9:57 am

Ah, key information! Thanks.

So even weirder - Mazda swapped the rows of relays round between the 2L and V6 petrols then.

A quick update - I grounded the wire at the connector up to the clock spring and the horns sounded. So it's definitely either the clock spring or horn switch. Judging by the general good condition of the electrics on Barry, my money is on the switch - they are the bit that tend to take a pounding ;)

So no avoiding air bag cover disassembly...
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Re: Horn not working

Post by mitchelln » Thu Aug 10, 2017 12:22 pm

Right. Braved the airbag and got to the horn switch. That thing was built for pounding!

Image

No way the steering boss could not be grounded right? So not looking good for the clock spring unfortunately. Although it looks pretty mint. It does have 3 spare wires though, so there is a possibility for a bit of re-purposing if the existing wire is actually broken. When I get home I'll ground the actual wire to another earthing point and see what happens.Fingers crossed!
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Re: Horn not working

Post by mitchelln » Thu Aug 10, 2017 9:01 pm

Fixed! :D

Exactly as I originally suspected - a chopped wire due to a mod.

There was an extra little light fitted to the centre console. Whoever did it picked up permanent power via (you've guessed it) the horn feed. To compound this, they decided to pick it up inside the steering column cowling using (you've guessed) it, a scotch lock. This is why I hadn't spotted it until I started looking round the clock spring. This had cut the wire leaving the downstream horn switch disconnected.

To add insult to injury, the light was a ghastly cheap thing. That's come off now!

The silly thing is this botch wasn't even correct. There is only 12V on that wire via the horn relay coil. If the light wasn't an LED it would probably have triggered the relay when switched on.
Last edited by mitchelln on Thu Aug 10, 2017 9:31 pm, edited 2 times in total.
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Re: Horn not working

Post by Bob » Thu Aug 10, 2017 9:03 pm

Bingo. =D>
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