wiring loom question esp: horn connection/ whats what

Starvingphotog said:

I'm confused from this. I'm rewiring my Combat and installing a Lucas braided wiring loom and the diagram and the loom show the ignition coils as Yellow/White and Yellow/Black.

Equally, the ballast wiring on the diagram and the loom is Blue/White and Yellow/White. I wired the bike according to the diagram and the colors on the loom wires, and did't run into any issues with matching the wires from the loom to the diagram, and the components. Is the diagram wrong? Are the colors wrong? Did I wire the coils and ballast incorrectly?

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Ok, so the harness yellow/white (correctly white/yellow 'WY') and Lucas diagram WY runs from the ballast resistor to both coil(-) terminals (the original factory wire was white/purple but wasn't marked as such on the factory diagram).

Blue/white (white/blue 'WU' as there is also blue/white 'UW' = High beam) runs between the handlebar kill switch WY wire and the ballast resistor, so from the kill switch it's WY, then WU to the ballast resistor then WY again to both coil(-) terminals.

Yellow/black (black/yellow 'BY') is the LH cylinder/coil(+) to contact breaker points and condenser (normally the LH points set as you look at them) wire.
Also black/white 'BW' for the RH cylinder/coil(+) to condenser/points.

There was very few spade connectors. Horn. rectifier and Zener diode are the ones that comes to mind. Maybe some more.

Mike40M said:

There was very few spade connectors. Horn. rectifier and Zener diode are the ones that comes to mind. Maybe some more.

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If you were reading from the first post then it turned out not to be a spade connector.

L.A.B. said:

Ok, so the harness yellow/white (correctly white/yellow 'WY') and Lucas diagram WY runs from the ballast resistor to both coil(-) terminals (the original factory wire was white/purple but wasn't marked as such on the factory diagram).

Blue/white (white/blue 'WU' as there is also blue/white 'UW' = High beam) runs between the handlebar kill switch WY wire and the ballast resistor, so from the kill switch it's WY, then WU to the ballast resistor then WY again to both coil(-) terminals.

Yellow/black (black/yellow 'BY') is the LH cylinder/coil(+) to contact breaker points and condenser (normally the LH points set as you look at them) wire.
Also black/white 'BW' for the RH cylinder/coil(+) to condenser/points.

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LAB, thanks for your reply and advice! I know this is a hard conversation to have over text and much more efficient by voice but I appreciate your patience. My Combat came to me without the horn working, without the signal indicator lights on the front and back, with only the LH main switch on the handle bar (the RH side was removed when they switched the hydraulic brake to a brembo setup), without the high beam working, and without the stop lamp work (just the rear lamp was wired and working).

So from the first paragraph, I can see that you were just pointing out the color discrepancy and it looks like my use of the Lucas diagram an wiring loom is correct in that the colored wires matched. I should mention that I did read an earlier thread where it was noted that the Warning Light Assimilator and the Blue Lamp Flasher wires on the Lucas diagram are reversed, and the Warning Light Assimilator (Red and Brown/Blue) is actually the 12V accessory connection. So that confusion got sorted.

The second paragraph is welcome information for sure. This is because I would like to use one of the push button switches on the LH switch as the kill switch. The toggle I would like to use as a high beam for the headlight, and the other push button switch I would like to use as the horn. I'm not sure which color coded wire in the bundle coming from the master switch is for which switch (i.e top or bottom push button or the toggle). I can see that I have individual White/Yellow, White/Red, Green/Red, White/Green, Brown/Green, and solid White wires coming out of the grey wire bundle. From your explanation in this paragraph it looks like I could run the White/Yellow, and it's matching wire, (or any other pair) from the switch between the Blue/White wire of the ballast and have myself a kill switch. Do you know which pairs I could use on this LH switch to make that happen for the lower push button? Also, the wire pair for the upper push button for use as the horn. And finally, the wire pair for the toggle switch to use as the high beam. What I'd like to do here isn't included in any manual or diagram that I have so I'm just muddling my way through it.

Final question is whether there's a correct way to read the color coding on these wires. I see some with a thin color band and some with a thicker color band. And your note in the second paragraph of the white/blue blue/white combination got me thinking that I may be mis-interpreting like for like wires.

Starvingphotog said:

The second paragraph is welcome information for sure. This is because I would like to use one of the push button switches on the LH switch as the kill switch.
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From your explanation in this paragraph it looks like I could run the White/Yellow, and it's matching wire, (or any other pair) from the switch between the Blue/White wire of the ballast and have myself a kill switch.

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The upper button is the kill switch button with the white/yellow (WY) wire.

Starvingphotog said:

The toggle I would like to use as a high beam for the headlight,

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The toggle is intended for the direction indicators/blinkers, green/white GW and green/red GR from the switch cluster so it has three switch positions but could be used for the headlamp High/Low beams although it would have a 'dead' central toggle position (unless a changeover relay was used).
Brown/green is actually light green/brown LG/N, and originally the feed from the flasher relay but to use the direction indicator toggle for the headlamp Hi-Lo then LG/N needs to be connected to the "Two Position light switch" blue U wire.

White/red WR is the 'spare' button so that could be used for the horn (connect WR to PB) but not as a kill switch because the spare button is a 'normally open' switch whereas the kill button switch is 'normally closed' although the spare button/switch could be made to operate as a kill switch with a (normally closed) relay.

Starvingphotog said:

Final question is whether there's a correct way to read the color coding on these wires. I see some with a thin color band and some with a thicker color band. And your note in the second paragraph of the white/blue blue/white combination got me thinking that I may be mis-interpreting like for like wires.

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The main colour is normally given first then the tracer colour and that's how they are identified on the factory wiring diagram in order to avoid confusion as there can be, for instance, white/blue WU (white with a blue tracer) and blue/white UW (blue with a white tracer) which are two completely different wires.

Mike40M said:

There was very few spade connectors. Horn. rectifier and Zener diode are the ones that comes to mind. Maybe some more.

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Rear brake switch has two spades.

Note that the left and right switch clusters can be swapped over left/right bar ends such that the turn signal switch can be on left hand side (was on right side my bike) and high beam on right etc.

Tornado said:

Note that the left and right switch clusters can be swapped over left/right bar ends such that the turn signal switch can be on left hand side (was on right side my bike) and high beam on right etc.

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Yes, the factory later reversed the switch clusters, however, Starvingphotog's Commando only has only the one switch cluster that the wire colours identify as the 'kill button', 'direction indicator toggle' and 'spare' button cluster.

L.A.B. said:

The upper button is the kill switch button with the white/yellow (WY) wire.



The toggle is intended for the direction indicators/blinkers, green/white GW and green/red GR from the switch cluster so it has three switch positions but could be used for the headlamp High/Low beams although it would have a 'dead' central toggle position (unless a changeover relay was used).
Brown/green is actually light green/brown LG/N, and originally the feed from the flasher relay but to use the direction indicator toggle for the headlamp Hi-Lo then LG/N needs to be connected to the "Two Position light switch" blue U wire.

White/red WR is a 'spare' button so that could be used for the horn (connect WR to PB) but not as a kill switch because the spare button is a 'normally open' switch whereas the kill button switch is 'normally closed' although the spare button/switch could be made to operate as a kill switch with a (normally closed) relay.



The main colour is normally given first then the tracer colour and that's how they are identified on the factory wiring diagram in order to avoid confusion as there can be, for instance, white/blue WU (white with a blue tracer) and blue/white UW (blue with a white tracer) which are two completely different wires.

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Again, great information here LAB. Question about the cluster switch thought. How is the loop for the switch done? For the first bit on connecting the kill switch using the WY wire from the cluster switch to the one end of the ballast resistor, how do I complete the loop to that same end of the ballast resistor, because the other end of the ballast resistor is continuing on to the coils through the other connection with the main loom for its loop. Same thing goes for the horn. I'm figuring there are wire pairs for each switch in the cluster switch. Am I wrong here?

Also for using the toggle switch for high-low beam, I'm having trouble following that since I currently don't have a blue wire coming from my two-position headlamp switch (I unplugged all the wires and it's sitting on my bench). Let me think on that though and see if I can figure out what you're advising.

L.A.B. said:

Yes, the factory later reversed the switch clusters, however, Starvingphotog's Commando only has only the one switch cluster that the wire colours identify as the 'kill button', 'direction indicator toggle' and 'spare' button cluster.

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Yeah, sorry, the name's Rob guys. LAB is correct. I only have the cluster on the left side of the handle bar. I have no idea which side it originally was mounted when the bike was originally made in England. I only have the wire colors coming out of the grey conduit to go with. I'm actually trying to figure out how the switch cluster works considering my education in electrics is that a switch has two poles and therefore two wires and I'm trying to figure out if each of the two push button switches, and the toggle switches have corresponding wire pairs to complete my idea of how a switch is made and works. Kind of an elementary electronics class here for me.

Cheers,
Rob

Starvingphotog said:

Question about the cluster switch thought. How is the loop for the switch done? For the first bit on connecting the kill switch using the WY wire from the cluster switch to the one end of the ballast resistor, how do I complete the loop to that same end of the ballast resistor, because the other end of the ballast resistor is continuing on to the coils through the other connection with the main loom for its loop.

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You don't need any additional "loop" wire connection at the ballast resistor (check how the ballast resistor is wired on the factory diagram).

Starvingphotog said:

Same thing goes for the horn. I'm figuring there are wire pairs for each switch in the cluster switch. Am I wrong here?

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The feed to the switch cluster is white W so the single W provides power for both button switches.

Starvingphotog said:

I'm having trouble following that since I currently don't have a blue wire coming from my two-position headlamp switch (I unplugged all the wires and it's sitting on my bench).

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In that case, all you need to do is connect the LG/N directly (or with an extension wire) to the headlamp switch.
There must also be a feed to the headlamp switch from the master switch in order to power the headlamp which on early '72 production was brown/green NG and later '72 it was blue/yellow UY.

LAB, thanks again for this input. I'm going to take a little break from the wiring and come back to it when I've had some time to work through the logic of the wiring. I know it isn't complicated, but for some reason my mind is making it so. I think your advice will take me to where I need to go. I'll touch base again, later in the week, once I've got the wiring completed. I plan to do a double check of my work before I connect the battery. I'll touch base before that.
Thanks again for your help.
Cheers,
Rob

Actually, one thing that will help me too is whether you have a diagram for wiring the two-position headlamp switch.

Cheers,
Rob

Starvingphotog said:

Actually, one thing that will help me too is whether you have a diagram for wiring the two-position headlamp switch.

Cheers,
Rob

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Only two wires need to be connected and the connections aren't critical as 34660 is just a two-position switch.

If it's an original 34660 two-position switch (should be marked on the switch as there are similar versions of this switch (34660 now unavailable new replaced by 31780) then I would expect it to have tabs at positions 5, 6, 7 & 8 (marked on the bottom of the switch).

If you connect one wire to 7 and the other to 8 (either way) then I believe it should work as intended (as I don't have a 34660 switch to test).

Yep. Mine is the 34660B switch - engraved on the side. It also says 71, which I think is referring to the year it was produced.

Do you know which color wires attaches to the switch?

Easy to determine which switch terminals are opening closing when toggling by using a simple test lamp or Ohm meter. Very useful tools when doing electrics. Not expensive.

Starvingphotog said:

Yep. Mine is the 34660B switch - engraved on the side. It also says 71, which I think is referring to the year it was produced.

Do you know which color wires attaches to the switch?

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I know you have the Wassell 'Lucas' main harness section but do you also have a new Wassell Lucas headlamp harness section or are you going to use the original Lucas?
Also, is the master switch an original Lucas and does it have 3 or 4 terminals, or is it a modern replacement switch?

As I mentioned previously, there was a change made to the harness in early '72 when the 3-terminal master switch was replaced with the 4-terminal switch (both 4-key position) and an additional separate UY headlamp feed from the 4th master switch terminal to the headlamp switch, therefore, if the headlamp harness is the later original Lucas or Wassell Lucas then one of the headlamp switch wires will be UY.
Because you will be using the direction indicator/blinker toggle as a substitute headlamp dip switch (High-Low beam) then the other switch wire is LG/N from the switch cluster, Edit: which will need an extension wire so connect LG/N to headlamp harness U or, the headlamp switch could simply be bypassed by connecting LG/N from the switch cluster to the main harness UY.


If, however, the headlamp harness section you intend to use is the 'early' original Lucas and/or it has the Lucas 3-terminal switch or modern replacement switch then call back.

Considering that the blinker switch is center-off, if you're going to use that as a high/low beam headlight switch then you don't actually need the switch in the headlight shell.

A little late, just caught up, maybe help.

Lineslinger said:

A little late, just caught up, maybe help.

View attachment 81381

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There are a few errors on that diagram.
The one below is accurate.



Edit: The white/blue marked "Main Loom" on the Trust Lucas headlamp diagram should be blue/white and marked R/H Switch.