Horn relay wiring question

[stevegt6]

I seem to have mis-placed the original horn relay - stumbled across it on Tuesday eve and put it safe and now cannot find it lol (found some other 'lost' bits though  :)

I do have several other relays of varying ampage, but all 4 pin

Anyone know what wire would go on which pin....?

I'm guessing the 12v (twin purple) will be pin 30 (???)

purple/black pin ????

purple/yellow pin ????

would an earth be needed on the forth pin...???

Cheers
S

[John Bonnett]

8735 wrote:

I seem to have mis-placed the original horn relay - stumbled across it on Tuesday eve and put it safe and now cannot find it lol (found some other 'lost' bits though  :)

I do have several other relays of varying ampage, but all 4 pin

Anyone know what wire would go on which pin....?

I'm guessing the 12v (twin purple) will be pin 30 (???)

purple/black pin ????

purple/yellow pin ????




would an earth be needed on the forth pin...???

Cheers
S

I think the original relay had only three contacts with an internal connection from the coil to one side of the contacts. If you use a four terminal relay most of which are at least 20Amp and therefore suitable. You can either T into the green power feed or, much better, run in a new cable providing a live all the time 3 Amp feed to pin 30. Connect the wire that goes to the horn push (purple/brown) on to pin 85. When you operate the horn push this will earth and make the circuit to operate the relay contacts. You will then need a 20Amp constant feed (green) for pin 87. The wire from Pin 86 (purple/yellow) goes direct to the horn and the other wire from the horn to earth.

I hope this helps.

John

[stevegt6]

Thanks John - Think i've got it.....let me see if i follow you....

The 'new'  live wire (lets use red) to pin 30 - this would come direct from battery via fuse, yes..??

my purple/black (horn push) to pin 85

my twin purples (loom 12v) to pin 87

my purple/yellow (to horns) to pin 86

85/86/87 wires are all terminated out from loom where original relay would be (for the 3 pins on the original relay as you say)

This i believe will make the horn available all times, yes..?

Cheers
S

[John Bonnett]

8735 wrote:

Thanks John - Think i've got it.....let me see if i follow you....

The 'new'  live wire (lets use red) to pin 30 - this would come direct from battery via fuse, yes..??

my purple/black (horn push) to pin 85

my twin purples (loom 12v) to pin 87

my purple/yellow (to horns) to pin 86

85/86/87 wires are all terminated out from loom where original relay would be (for the 3 pins on the original relay as you say)

This i believe will make the horn available all times, yes..?

Cheers
S

That should work Steve. You could pick up a live from the battery or the solenoid and fit an in line 3Amp fuse as a feed for the relay coil. I did write purple/brown for pin 85 but I meant purple/black; sorry. You are correct that the horn should work with the ignition off. I thought the power came in on a green lead but having looked at a picture of my car as it was originally I can see that it is purple. So let's hope it works. Fingers crossed.

[Richard B]

8735 wrote:

The 'new'  live wire (lets use red) to pin 30 - this would come direct from battery via fuse, yes..??

If you use Brown, that fits the electrical Standard for live, non-switched that Triumph used.

[stevegt6]

Richard_B wrote:

If you use Brown, that fits the electrical Standard for live, non-switched that Triumph used.

...and i happen to have some brown too :)

Thanks guys  8)

[drofgum]

Richard_B wrote:

If you use Brown, that fits the electrical Standard for live, non-switched that Triumph used.

Hi,
Brown is for unfused and unswitched. Violet or Purple is for fused, unswitched. The Mk1 and Mk2 Spitfires fed the horn through an inline fuseholder. The wire that fed the fuse was Brown. The wire the fuse fed was Violet. "Switched" in this case means ignition switch controlled.
                                                                       Pedantically,
                                                                       Paul
Later: I see little harm in making a jumper with a piggyback terminal at one end to join terminals 30 and 87 of the relay.  That seems simpler than running a new fused wire to feed terminal 30.
                                                                       Paul

[stevegt6]

Beep-Beep  :)

Horn now working - did new wire....but guess the 'piggyback' option is there too if i ever need an extra fuse space

Thanks guys