11 replies to this topic

[eyepeeler]

I have a horn that is not working, I have taken the steering wheel off and checked the contacts between the actuator and the copper ring behind, that s ok. I have 12v at the relay in the engine bay, I checked the black wire and one of the green wires, the other green wire I got no reading. I got a cable and touched the contact on the horn and the positive of the battery and got a noise, so horn worked that way. Does anyone know how to test the relay??

[A9X]

yep, you'll need a 12-volt test light or a voltmeter. Start by testing for 12 volts at the connector to the horn. One side of the circuit is earthed, so you'll need to check between a good ground point and the wiring connector for the horn. A simple SPST relay will have a constant supply of 12 volts to it, a lead that runs through the harness to the horn, another lead that runs to the horn switch in the wheel, and a ground. Check that voltage is coming into the relay and leaving it when the switch is pushed. If it's not, try grounding the lead that goes to the horn button to make the relay pull in. If the horn sounds, the relay is good but the horn button or its wiring is bad. You may be able to simply replace the relay if it's the problem.

[eyepeeler]

Thanks for the info Mark. Will have a look at trying that. Behind the steering wheel is the copper contact button that the horn actuator runs over, if I do an ohms test between that and the relay spade connector it should have no resistance, is that right? I am wondering if there is a problem there. Cause I am tring to determin wich green wire is the wire back to the steering colum. The relay does have a constant 12v supply by the way.

[A9X]

i have a wiring diagram here if that helps

[eyepeeler]

i have a wiring diagram here if that helps

Cheers Mark, I found a wiring diagram for the car and tried what you suggested. There was a fault with the wiring between the relay and the column. The wire was broken off at the spring loaded contact for the steering wheel, had to take out the indicator assembly to work that out! As I said before the horns worked when I tested them from the battery, I can now hear the relay working but no horn. Did a volt check at the terminal of the horn when the horn button was pressed and got 12 volts at the terminal. Has anyone taken the horns apart or know how to service them?

[eyepeeler]

Just a further note, I can intermittently get the horn to work directly from the battery. When I try it from the horn button I can hear the relay and if I keep holding the button the fuse blows. There must be a lot of resistance in the horn coil? I took the small one apart to have a look and found a bit of rust inside, cleaned it up with a bit of emery cloth, nothing more and got no better result, still blowing fuses. Anyone know how to service and how the horn bits inside the horn work?

[FastEHHolden]

Horn not working?


Watch for finger !

Edited by FastEHHolden, 11 August 2012 - 09:41 PM.

[eyepeeler]

Horn not working?


Watch for finger !

LOL .

[eyepeeler]

Craig,

I have given away or sold off all my reference books so I am running on memory and I just opened up a horn relay to investigate but I think you are almost there.

Think of this as two independant circuits.

1/ Horn relay:- The coil of the relay uses two connection of the three on the relay bottom. One is connected to +12V from the fuse box and the other connects to the horn ring that "earths" the other side of the circuit when pressed...........This I think you have fixed.

2/ Horn(s):- The relay when energised puts the same supplied +12v out on the one remaining connection on the relay (green wire from memory). The other side of the circuit for the horn(s) is connected to earth through their casing. If you are blowing the fuse with prolonged operation then as others have said, you have a dud horn. The low pitch snail is common but the high note (small one) is difficult to find.

My suggestion as you are now part of the (OMG) anal owners brigade, is site down, pull them (horns) apart, work out how they work and clean them up. They are very simple. Basically they oscillate by moving and armature once energized which opens a contact in the supply circuit which means they de-energize the coil and try to return to the rest position, but this re-closes the contact in the circuit which makes the horn move again which again opens the contact and so on as long as the power is applied.

You may have a genuine insulation break down in the coil or the armature is not oscillating properly and the coil is remaining energized or remaining energized for too much of the duty cycle. For example, if the coil is normally energised for 30% of the cycle but is now 80%, the end result is more current flow overall. This may all be down to wear and tear.

Good luck, I am sure you will work it out.

Cheers Darky, that helps a fair bit. I can see what you are saying from what I saw when I took the high note horm apart. There is a fair bit of rust in there, will take it apart and give it a really good clean up, never know, it might work again. So the high note horn is hard to find?? If you sold or gave to someone a diagram of the horns can you ask them if I can get a copy of the info?

You heading to West anytime soon, I remember you came over a bit a few years back? Would be good to catch up anyhow. I will be back for All Torana Day in November in any case.