I am a Commando owner since one week now and need to get it past the road test. Just discovered the horn is not working...
I am unsure which button should activate it: the indicator switch is on the right (European model) and the buttons above and below do nothing visual or audible. The headlight flasher is top left and the other switches on the left seem to do nothing.
There are a couple of wires (red and blue/brown) not connected to anything and they show 12v no matter what button is pressed. I think I can see the horn and 2 (possible empty, can't really see) connectors behind the rear mudguard.
1. Could they be the horn feed?
2. Which button should be for the horn?
3. Assuming it is top right, how would I trace the wires? Is there a junction box somewhere?
3. If I wanted to check the horn directly (if I can reach it with probes) does it matter which is +ve and which is -ve? I can't see any indicator on the connectors.
I am a bit of a beginner here so would appreciate any tips.
Graeme
Vienna, Austria
I've since found out from…
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The Commando horn is not…
The Commando horn is not fussy as to which way round you decide to wire it up.
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Location !
The Commando horn can afford not to be fussy. No-one can get to it to teach it the error of its ways ! :-)
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Graeme. Major tip, go to the…
Graeme. Major tip, go to the RGM Norton site and look at the workshop manuals page.
PART NO: 06514 could be the one that you require?
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Hi Paul - I didn't see a…
Hi Paul - I didn't see a part with that number, or did you mean the actual workshop manual part number 065146 ? Which is not available right now :-(
Anyway, I was not permitted to do my MoT test (or the Austrian equivalent) because I don't have an official paper with weights etc. and I cannot find out the date of first registration - my Italian certificate only has the year but the Austrians insist on an exact date.
More research to be done...
I did however get to ride it today for the first time, using special dealer plates. What a machine!! Looking forward to fixing it and getting it legal.
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Hi Graeme. Andover Norton…
Hi Graeme. Andover Norton have the manual.
06.5146
WORKSHOP MANUAL 750/850 1970 - 1974
Note the year, perhaps this covers your model?
It has a number of wiring diagrams covering the Commando from pre 1971 to 1971/72/73.
Invaluable to anyone who wants to see the best results from their efforts.
Andover have their own numbering system similar to part numbers but they incorporate a full stop as above.
People say that the British invented bureaucracy, now it looks as if Austria is plagued with it to a greater degree.
Rgds.
Paul.
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This could be easy.
Dealing with the original problem. The horn is virtually inacessible, on the front bottom of the rear mudguard. The easy answer to is to fit a new item as and where you can. Wiring-IF it is ORIGINAL wiring then the two connectors seen above are NOT the ones. The RED is an earth and the BRN/BLU is battery live. The original horn wires are as follows-Is this a 750 with the 2 position ignition switch? If so the horn will be fed with a BRN/BLU and 'made noisy' by a BRN/BLK (earth) fed from the handlebar switch. IF this is an 850 with the 4 way ignition switch. Then the horn will have a RED earth and PPL/BLK (live) from the handlebar switch which in turn is fed with a WHT from the ignition switch.
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An easy way to test the switch or horn
Connect the side of a light bulb to the brown and blue wire and then touch the other bulb terminal onto the aluminium casing. The bulb should light as this wire is a permanent live.
Connect the side of a light bulb to the brown and blue wire and then touch the other bulb terminal onto the red wire then press the horn button the bulb should light. If not try pressing the bake lever as this wiring could be for the brake light switch.
If the light:
doesn't light the switch is faulty;
does light the horn is faulty.
Let us know the outcome.
The attachment shows the basic wiring for a horn. Ignore the polarity and wiring colours it is from a book I wrote some years back.
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Easier than expected
With the battery cover removed I could easily see that the wire had simply slipped off the horn connector. I managed to get it back on the a pair of narrow pliers. So I spent time polishing the bike instead of removing rear wheel and mudguard. Happy day.
Can someone tell me the purpose of the live wires shown in my photo above though? I've read about attaching shavers etc, but there is a connector for that also attached to the battery.
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On the LHS side...
On the LHS side of the frame on the Commando (750) is a two pin socket, (very often associated with 12V supplies inside caravans) Such a socket should have live (BRN/BLU) and and earth (RED) But the two wires on the Socket are very small ring terminals. The questioned connectors appear to be Luca. They are the correct colours for the 2MC but that has a smaller Luca on the earth, also the 2MC wires shouldn't be able to come that far down on the bike.
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I've since found out from other posts that the lower left button should be for the horn.
Now I just need to find out how best to trace that...