Switch cluster questions

TT

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Mar 7, 2005
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I have some questions about Commando 850 Mk IIa headlights and switch positions.

When I replaced my front brake master cylinder I appear to have lost my headlight low-beam (I think). The manual seems ambiguous about how the lights are turned on.

Should the main headlight beam come on when you push the toggle switch on top of the headlight to the right? Does high-beam come on when you switch the right handlebar lever (up or down?)?

At the moment one of the beams comes on only when the headlight switch is toggled to the right and the right handlebar switch is depressed.

My indicators are on the left cluster.

I have had the right-hand cluster apart and the buttons and switch work. Reassembly with the switch lever ball-bearing was quite easy after 10 to 20 attempts.

Obviously I don't do much riding at night.
 
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TT, I have the same model with turn signals on the right cluster. High beams come on full time with left hand toggle up and headlight toggle switch to the right. Left upper button is for flashing high beam when using low beam lighting. Lower left button is the horn. Lower right pushbutton is the kill switch and upper button is not used.
 

L.A.B.

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TT said:
Should the main headlight beam come on when you push the toggle switch on top of the headlight to the right?

The switch should be a simple OFF/ON switch, and (reading from the wiring diagram) a blue/yellow wire from the harness to the off/on switch and a blue from the switch goes to the handlebar switch unit.

TT said:
At the moment one of the beams comes on only when the headlight switch is toggled to the right and the right handlebar switch is depressed.

Do you mean by "right handlebar switch is depressed" that when the centre toggle switch is clicked 'down' one beam is coming on, as that would (hopefully?) indicate you are at least getting power to the switch unit from the lighting switch (and that one side of the high/low switch is working)?

Or are you referring to pushing one of the button switches 'in' as there should be a separate supply (white wire) that does not run through the lighting switch that is used for the headlamp flasher button supply (so something could possibly be connected up wrong)?

TT said:
My indicators are on the left cluster.

The 74 rider's instruction handbook shows the switches in the reverse position to that.

So the left hand switch would *normally* operate the headlamp flasher (top button), high/low beam (centre up/down toggle), horn (bottom button).

Right hand switch = top button has no function, centre toggle = indicators, lower push switch =kill switch.
(as mkjen had posted up as I was typing this)

There should also be a blue/white from the handlebar switch that goes to the headlamp main (high) beam (and warning lamp), and a blue/red wire to the dip (low) beam.
 

TT

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LAB,

This is more difficult to describe than I thought. I am considering moving the indicators to the right-hand side and the lights cluster to the left hand side - just to be in sync with the forum.

When the headlight toggle is switched to the right nothing happens. Then when I siwtch the right-hand centre toggle I get the headlight to work. Also depressing one of the right-hand buttons turns the headlight on.

I am not at my bike as I write this..

From your message it appears that low-beam is missing in action.

I will look inside the headlight shell tonight.

Thanks.
 

TT

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LAB,

I have re-read your post and reviewed the wiring diagram.

I think the problem is between the right-hand switch cluster and the headlight (low-beam). The cluster wiring is as per the electrical diagram.

As I understand it the blue wire provides power for 'dip beam' or by depressing the right-hand blade switch activating the 'main beam'. The Blue Wire is obviously providing power in order to get the main beam working.

Part of my confusion is the terms 'main-beam' and 'dip-beam'. As I previously stated the 'Dip Beam' not is shining.

Unfortunately I will not get back to the beast until Friday.
 
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Hi TT,

I concur with the other responses on locations and functions of the switches. I have a 74 Mk11a with the same arrangement. My toggle switch on the headlight has three positions. Far left is everything off, middle position is diplight on and far right is headlight and diplight on.
 
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more on the switch cluster

Sorry, I misspoke. By "diplight" I meant "pilot light". Middle position of my three-position toggle on the headlight shell is pilot light on, headlight off. I never ride with just the pilot light on (does anybody?) so if I were rewiring, I would either 1) install a two position toggle with headlight on or off), or 2) leave the 3-position toggle in the headlight shell for decoration but wire up the headlight directly and forget about going through a switch at all.
 

TT

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Problem sort of solved.

I traced the 'Dip Beam' problem back to the headlight switch. The Blue/Yellow wire has power but no switch setting provides power to the blue wire that goes to the switch cluster.

Tpeever - you said you have a 3-position headlight switch. Is this usual? Mine is a 2 position switch (as per the 1972 and 1973 wiring diagram).

In the short term I will bypass the switch by connecting the blue/yellow to blue wire in the headlight shell. The downside of this is that the Dip Beam will be on all the time - even when kickstarting.

As for the Main Beam & Headlight Flasher working while the the Dip Beam was dead - it doesn't make much sense. It appears to be drawing power from the white wire....Not what is in the manual.

Any good places to get a replacement headlight switch?
 

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TT wrote:The downside of this is that the Dip Beam will be on all the time - even when kickstarting.

The 1st position on the standard ignition switch is ignition only. 2nd position is ignition and lights. Do you have a modified ignition switch?
Mike
 
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TT said:
Problem sort of solved.

I traced the 'Dip Beam' problem back to the headlight switch. The Blue/Yellow wire has power but no switch setting provides power to the blue wire that goes to the switch cluster.

Tpeever - you said you have a 3-position headlight switch. Is this usual? Mine is a 2 position switch (as per the 1972 and 1973 wiring diagram).

In the short term I will bypass the switch by connecting the blue/yellow to blue wire in the headlight shell. The downside of this is that the Dip Beam will be on all the time - even when kickstarting.

As for the Main Beam & Headlight Flasher working while the the Dip Beam was dead - it doesn't make much sense. It appears to be drawing power from the white wire....Not what is in the manual.

Any good places to get a replacement headlight switch?

Not sure if 3-position switch is normal or not. Wouldn't surprise me if my switch is a Triumph switch as someone suggested!! I have found a few other "non-standard" parts on my bike and with a 34 yr old bike, sho knows what the previous owners did? Also, some of these British bikes had different parts straight out of the factory!!

Should be no problem having the headlight on during kickstarting as long as your battery is good and you are getting a good spark. As I said before, I always drive with the headlight on and never touch the headlight switch on any of my bikes. All I really need is a two-position ignition switch!!

Toggle switches should be available lots of places but I haven't been looking recently. I buy a lot of stuff for my bikes from AMR in Tucson, Walridge Motors in southern Ontario, Canada, Deluxe Cycle in Granite Bay, CA and Old Britts in Eumenclaw, WA. All of these places probably have them. I imagine these switches are available on eBay too. I think original Lucas ones are available but fairly pricey if you are a stickler for originality. Otherwise, there should be decent repro copies out there.
 

TT

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I am learning the hard way.... it turns out to be a blown dip beam bulb and a faulty switch cluster.

In my stuffing around I have somehow broken the headlight switch.

I have put in a temporary switch (AUD $3) which works a treat but doesn't look original.

It appears that PO has cut down a H4 halogen bulb to fit in the old style lens. To replace the bulb I need to go back to an old style bulb, buy a new reflector (and adapter) or cut down a H4 bulb.

I don't ride at night much but I like the thought of a good headlight and the ability to replace bulbs easily. Don't fancy being on the road and needing to replace a custom part.



Of to the shop for a lens, adapter, original switch etc....

mkjen - my ingnition switch is standard. I have never used the 1st switch position. Thanks for pointing that out.

tpeever - I will start looking for a repro switch..
 
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TT

Is there any reason why you just don't go for a sealed beam ?? Save yourself a few bucks .
 

TT

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Ron,

Good idea - sealed beam and new headlight switch installed - total cost $21 (Australian).

The headligh switch is an obvious non-standard item but the plastic toggle switch lights up when it has power. I like that.

I would be suprised if you noticed the non-LUCAS headlight. It is a bit crowded in the headlight shell but it works. I will keep my eye out for a non-sealed beam unit.

The switch cluster is also working correctly....

If I could start the beast all would be well.

Tony.
 
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