Sounds like another classic lucas earthing problem to me.

Dull horn sound before [low curent getting to the horn even then?]
No horn after good washing [no current getteing to the horn now?]

I'd try removing the horn assembly from the shell, clean up any rust from the mount braket and body with sandpaper, refit [get a good elecie contact happening.] do the same between the horn assembly and its bracket, & the wire contacts at the horn.

Considering the history of events, your problem is most likely in the engine bay

Thanks for the tips.

Yes my indicators work fine. I also think it's to do with something under the bonnet. I will check out what you suggest and make sure there is a good grounding on the horn.

Question: My original horn comes with 2 cables, one should be negative and the other is ground right? or does the horn body ground itself to the car?

Cheers

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Lillee - 1969 Morris Mini K

.mm

Now this is important. If your car has an alternator then it is a NEGATIVE ground (in the absolute majority if not all the cases). You could do lots of damage if youre unsure what negative ground is or whether your car is neg ground and you play with the wiring.

The easiest way to find out what direction it is is to look at the battery. If it is connected to the body at its negative terminal and a wire goes from positive to the solenoid then its negative ground and vice versa.

Now on a negtive earth car I know that there is grond to the stalk hence its constant positive to the horn and it cannot be grounded off the body. Ie you actuate the original electrical horn it by turning the ground on from the stalk hence it cannot be permanently grounded. For the air horn, just use the wires from the existing horn, relocate the air horn to a dry spot higher up, connect the existing positive wire (purple i think) to terminal 30 on the relay, run permanent ground to the relay and permanent ground to the horn, run a wire from the relay to the positive terminal on the horn and connect the wire from the stalk (black\purple ?) to the relay. Bingo.

Chong,
The 2 horn wires- one is 12V+ from the fusesbox, and the other goes up the column to be grounded to (-) via the horn button.

As Mike said, your car is NEGATIVE earth.
If you reverse the battery you will probably kill the diodes in the alternator....

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

yea its interesting why I kept repeating "negative ground" "negative ground" rather than earth. This use of the word ground is what creates the confusion for many people I reckon, by drawing non existent paralels with household electrical grounding.

OK i worked out what it could be... I have a flat battery!!! the Alternator is not doing it's job!!! could this be why my horn doesn't work?

Argh... I am tempted to retro fit a pulsar alternator and get rid of my battery woes once and for all... mmm 75amps...

I got quoted $150 for recoe'd 15ACR 28amp POS Lucas alternators... man I'd pay $220 for a new Bosch Pulsar one over that!

DAMMIT I JUST WANT TO DRIVE THE CAR AND HONK MY HORN!!!!!!!!!

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Lillee - 1969 Morris Mini K

Meh my horn stopped working for about a year. Then miracleously it started working again. My horn is really pissy so I always used the exhaust and wheel spin to demonstrate my anger to people The problem with my horn is that the button is on the centre console, next to the wipers (ie: on the passengers side!) Thus it is a source of great amusement to the passengers, constantly beeping the horn as I do an Italian Job rendition driving along the footpath. Wouldn't want to attract attention or anything....

Strangely enough, when we plugged my horn into my brother commodore it was very loud! Maybe there is something in the Mini electrical system that automatically makes the horn sound cute!

Ok its an alternator off a '87 - '89 Nissan Pulsar fuel inj. model. You need the Bosch model not the generic one (I think its BOsch N13). Do not get the one off a Falcon if the wrecker offers its the same to them but the lower mounting point is too far out and might bump into the grill.

Because the alt is bigger than the Lucas you'll either need to change the lower tightening bar (the metal bar to which the alt lower mount attaches) by making a new one from some CURVED or angled sheet metal or the easiest way attaching a second CURVED bracket on top of the old one to elongate it. Curved is important so as to clear the alt. fan fins. Just pick up a mounting bracket from the wreckers.

On the left top mount (not the water pump one)youll have approx 2'' space between the mount and the alternator - put a big nut inthere or some washers anythingas long as you can achieve a perfectly tight fit so as to keep the alt straight. On the right make sure by using spacers or anything else that there's a really straight allign between the fan belt pulleys (the belt has to be straigh or itll burn and whine). I had to undo the alt nut to replace a spacer to get it in line.

Removing the main nut on the alt is a real horrible bitch of a job. Its done real, real, real perfectly tight and youre supposed to hold an allen key inside the shaft (its shaped for it) and turn the nut with a socket. Its really really hard so ask the wrecker to undo the nut with an air ratchet - much easier coz you just hold the fan blades. Even if you dont need to remove anything you can still do the nut up at home and it'll be tight enough - not ridiculouly tight.

Connections: Connect the point marked as B+ to the Starter solenoid (use a thicker wire if you wanna use the full amperage increase just dont go crazy with jumper wire etc). On the moulded plug there are two sides. One is marked L (thin white? wire inside the plug) this goes to the ign light wire. The other marked "E" I think (thicker red wire inside the plug) and it goes to a fused "on on ignition" +12v (you can use the existing wire from the Lucas alt but its connected to the unfused side of the fuse box. So either put it on the fused side or put an inline fuse. Do not confuse and mix the connections on the moulded plug or you'll fry up the internal control unit.

Thats it (only took me 1/2 hour to write for the second time). I had to splice and rewire the connections as they were joined through the old control module but you probably wont have to.

Sounds pretty easy. Is the Pulsar pulley a poly-V one then?

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Hey thanks for that Mike.

So doc sounds simple cept for that extra tightenning bar issue...

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Lillee - 1969 Morris Mini K

Heh, I got welders & spare adjusters... no problemo...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I have the twin horns; one High tone and one Low tone. They are marked H and L respectively, on the trumpet part of the metal horn. They are embossed in it and you cant miss them.

The Low horn has two sets of spade plugs, for the connecting lead to the High horn, so they are running in parallel. Really makes ya car sound larger... i'm serious!

OK, Chong now has Bosch Pulsar alternator in, charging happily. When he got here the old Lucarse 15AC was doing SFA...

Note the Bosch main 12V output stud is 8mm dia- make sure you got a nice big ring terminal crimp lug to suit..

I welded 2 Mini adjusters together to reach the alternator's bottom mount, which is closer to the grille than a Lucas.

Took out the spacer behind the pulley, and it lined up nice. Sweet!

Coupla pics..

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

She's Sweet!!! the lights are brighter, interior console lights are brighter, it's awesome now!!!

I also managed to put in the airhorns yesterday and it's also working a treat! I put in two small horns and left the big horns out. Nice high pitched beeeeeep! and boy is it loud!

I have to book Kev in for a pulsar dissy next You're a legend Kev, thanks for that! I owe you big time!

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Lillee - 1969 Morris Mini K