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Horn set up for LH

Started by _LHSL308_ , Jun 26 2013 10:39 AM

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14 replies to this topic

#1 _LHSL308_

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Posted 26 June 2013 - 10:39 AM

Just got my car back recently and am just trying to get my horn working again. The horn has a positive and negative prong but I cant seem to find the wire that connects to it to get it working.Possibly an earth wire connected to the wrong spot. Recently the engine bay was stripped and painted and everything was put back in. I have put the relay back and connected it with the plug. When I press the horn the relay clicks and then blows a fuse, maybe because the horn is not connected not sure.

If anyone's got a pic of how the wiring is connected that would be very helpful.

Cheers

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#2 hanra

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Posted 26 June 2013 - 10:55 AM

Do you have the original horn relay?

If so they have 3 terminals, H= Horn, B= 12v and S= Horn Button.

The horn themselves are grounded via the mounting of them to the body work, so this is the first thing to check with a DMM, ensure no paint is preventing it from having a low resistance to GND.

Confirm you have 12v going to the relay with a DMM.

Confirm that as you press the Horn button, it supplys a GND.

Brown wire to the Horn, Green wire 12v, Green wire Horn button just to make things confusing! With a DMM its basic stuff.

Edited by hanra, 26 June 2013 - 10:56 AM.

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#3 _LHSL308_

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Posted 26 June 2013 - 12:37 PM

I have a multimeter but I have never learn't how to use it, if you could give me a few tips on what to set it on that would be great?

I can confirm that when the fuse is good the relay clicks when the horn is pressed. Yes I have the original horn relay which has 3 prongs.

You might be right about the earth if the relay gets its earth through where its mounted, although I have it screwed to the body so you would think it would be getting an earth. I just can't find a wire that connects to the horn itself.It was connected and working before the engine rebuild and paint work was done.

Is the horn itself connected with both positive and negative or just one connection?If you could elaborate more on what GND means presuming ground, that would be good mate. Sorry I tend to leave car electrical stuff to the experts. Thanks for your help Brad.

Edited by Gonedeaf, 26 June 2013 - 12:43 PM.

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#4 hanra

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Posted 26 June 2013 - 01:02 PM

The relay does not need a GND (ground/earth). The horn does however, it wont work without it being well GND'd.

If your wiring harness is original, the horn wire is a singular green wire that connects from the H terminal on the relay to the horn.

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#5 _LHSL308_

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Posted 26 June 2013 - 01:05 PM

I do have the original wiring loom. I will have a look this afternoon. I still need to check the relay with the DMM, what setting should I have this set on?

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#6 hanra

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Posted 26 June 2013 - 01:11 PM

You simply need to check the wiring going to the relay with a DMM.

You are looking for the 12v supply to the B terminal, DMM set to Volts DC.

And you are looking for GND supply to the S terminal. DMM set to Ohms.

A singular green wire goes to the horn within your headlight harness.

Ensure the horn is grounded with the DMM set to Ohms.

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#7 76lxhatch

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Posted 26 June 2013 - 01:11 PM

The horn has a positive and negative prong

Is it aftermarket? The factory ones earthed through the body and only had a positive terminal (although some had a dual spade terminal).

Normally if the relay is clicking then its working fine and the problem would be downstream. The reason the relay does not have a direct earth is because that's what the horn button on the steering wheel supplies.

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#8 _LHSL308_

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Posted 26 June 2013 - 01:29 PM

I have 2 green wires at the left headlight. One green wire has 2 plugs on it and the other just has the one female on it. I also have one what looks like earth prong on the back of the headlight. I think this horn is a aftermarket one, here's 2 pics to confirm.

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#9 hanra

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Posted 26 June 2013 - 01:43 PM

Use the DMM on Ohms to measure continuity between the wire that connects to H on the relay and to the various unknown wires you have hanging around. Once you measure a S/C, thats your horn wire.

The horn is aftermarket, one terminal will need to be connected to GND.

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#10 hanra

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Posted 26 June 2013 - 01:54 PM

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#11 _LHSL308_

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Posted 26 June 2013 - 01:55 PM

Got it working thanks guys. Just one more thing what are the prongs that are on the back of the headlights, are they earths and if so are they used?

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#12 hanra

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Posted 26 June 2013 - 02:04 PM

What was the fix?

The headlight has 3 terminals. One is GND, one is Low Beam the other is High Beam.

The GND goes to the Rad support panel.

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#13 _LHSL308_

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Posted 26 June 2013 - 02:55 PM

Yep the negative from the horn was bolted to the radiator support panel. There was one green wire which had a female and a male and one green wire which had a female terminal. The single female was plugged into the male of the other wire and the female was onto the earth of the headlight, looks like it was connected wrong. Simply changed the wires around putting the single female onto the positive of the horn. Followed the green wire from the right hand headlight earth which now is connected to the left hand headlight earth. Working perfecto now.

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#14 _LHSL308_

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Posted 26 June 2013 - 07:48 PM

Drove the car this afternoon and everything went well. My oil pressure gauge had been on the blink for some time as well and even that started working properly today too, I am guessing it must have been something to do with the earth wires onto the left headlight.

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#15 _LHSL308_

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Posted 26 September 2013 - 05:23 AM

Drove the car this afternoon and everything went well. My oil pressure gauge had been on the blink for some time as well and even that started working properly today too, I am guessing it must have been something to do with the earth wires onto the left headlight.

Just to clarify. The oil pressure gauge stopped working shortly after this initial drive. The oil sender was found to be on the blink and when replaced with a new one, oil pressure gauge has been working flawlessly together with the horn.