120 horn replacement

[tony rodaway]

Hello guys .
I'm a bit puzzled how to replace my sad sounding horn with a more modern horn.
The horn I got is off a vauxhall astra and works perfectly as went directly to my battery and horn went off.
My problem is the original horn has 2 horns with 2 separate plugs.
It has 3 wires all the same colour and is earthed from the car body.
I'm confused how the new horn works as have tried every combination but no joy.
Not sure what I'm missing but probably some simple factor.
These are the horn connectors all the same colours.
Has any one done this small modification to there 120.

 

[karl2000]

Bit confused with this - is the problem you dont know what the wires on the astra horn are for?

But youve tested it?

 

[Tractionman]

Years ago, I changed the horns on my 78 as they were feeble. I had a high and low tone from a Fiesta, and although both horns worked off the battery, could never get them to work wired to the 78.
Like you Tony, I tried all sorts of combinations.My thoughts were at the time, the negative wiring on Toyota's ( dont know what the Fiesta's were), or they needed a relay, I gave up and left originals. Let's see where this goes.

 

[tony rodaway]

Bit confused with this - is the problem you dont know what the wires on the astra horn are for?

But youve tested it?ÿ

Only 2 wires on the new horn.
Tried direct onto my battery with testing the 2 wires either way round and both ways the horn works from positive and earth what ever way I connected them to the battery.
The oem horn works with the original connections but only if bolted the the body for earth.
How can I find the power with the wires all one colour.

 

[Tractionman]

Have someone turn on ignition and press horn, while you dab each wire in turn on your tongue.
(Not serious, haha)

 

[tony rodaway]

Landcruiser horn works with out ignition but I tried ignition on anyway with each combination and no joy.
Puzzled is an understatement.

 

[karl2000]

Have you tried multimeter?

 

[Tractionman]

Best dea, or even a 12v test screwdriver

 

[karl2000]

It looks like theres just one positive wire (green/red) from the horn relay that gets split into two - one goes to each horn - one high tone and one low tone. The horn gets its earth from the body.

.... Or is it more complicated than that?

 

[tony rodaway]

Just reading other posts it's seems more complicated than that as in fact a relay is needed apparently so going to do more research and post my findings.

 

[tony rodaway]

Found this post on Google and says an easy swop is not as easy as it looks.

 

[karl2000]

Theres already a relay though?

 

[karl2000]

Hmm thats like having the load side of the existing relay activate the control side of the new bosch relay. Whats the point?

 

[karl2000]

Just had a read of that - i think its because theyre fitting massive horns that draw much more current than the OEM horn - so much more current it would possibly blow the fuse. I doubt youd have the same issues with an astra horn though? Horn fuse look to be 10amp, what was it on the astra?

 

[tony rodaway]

I bought the item from eBay and the horn it's self is in good health.
I have checked fuses and replaced just to be sure and still no working function.
I'm a bit stumped on this simple looking install.
I have re installed my oem horn and back to normal function until I find a solution.

 

[karl2000]

Where did you ground the astra horn? Either it should work or it should blow the fuse (if it wants substantially more than 10A), nothing else makes much sense to me.

 

[tony rodaway]

Astra horn as I said only has 2 wires and connected direct to the battery the horn works perfectly.
I connected the astra horn to my wire harness in everway possible and had it bolted to the body for the earth but no joy.
Was hoping someone one here had changed there horn as yes all lc,s sound like a strangled chicken.
The only clip I found on YouTube was a guy changing his horn with a louder horn from toyota and just clips straight into the oem harness so that was useless.
How can 3 wires the all the same colour power one item and not another with same working parts.

 

[tony rodaway]

Just reading some facts on this issue is that apparently the voltage is to low to power the astra horn.
I will try the relay option and see if that works and see if I can resolve my issue.

 

[tony rodaway]

Where did you ground the astra horn? Either it should work or it should blow the fuse (if it wants substantially more than 10A), nothing else makes much sense to me.

Earthed to the body via the bolt that holds it on.
Oem horn only works when bolted to the body via the bolt provided.

 

[tony rodaway]

Just had a read of that - i think its because theyre fitting massive horns that draw much more current than the OEM horn - so much more current it would possibly blow the fuse. I doubt youd have the same issues with an astra horn though? Horn fuse look to be 10amp, what was it on the astra?

Sorry Karl not got a clue of the astra fuse voltage as it was on ebay.