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#710882 - 10/08/17 4:16 pm Tail light going off on advancing key.  
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btour Online content
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Hi all, Bit of a problem. T120. '71'. Issue is this. On first advance of ign switch, power on to start, the tail light goes on. On second advance, ign plus lights, the tail light goes off. Brake light does not work in any position. Bulb was fried, both filaments. (btw, what is that bulb?) I forget a lot.

I seem to remember having this problem before and it was related to the rear brake, sending switch. Can some one confirm or elaborate? Everything was working fine when the bike was stored for a few years. Seems weird to have this problem occur. But everything is weird, especially with these bikes. smile

Not much time left in the season, and I got get this right fast. I had a great ride last night. Probably went too far from home for this shake out trip. Fortunately a nice policeman was so impressed with the old bike he let me drive home.

Correct the above to: In first clockwise advance, rear light goes on. No idea if it is the brake filament or running light. There is no change of brightness when the brake is applied..There is no rear light at all with the next clockwise advance of key switch.

Last edited by btour; 10/08/17 10:21 pm.

Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
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#710907 - 10/08/17 8:44 pm Re: Tail light going off on advancing key. [Re: btour]  
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Hi Bob,

Originally Posted by btour
T120. '71'.
On first advance of ign switch, power on to start, the tail light goes on. On second advance, ign plus lights, the tail light goes off. Brake light does not work in any position.

Could be several causes, and a combination.

1. By "advance", you mean turning the key clockwise from the vertical 'all off' position? If so, what happens if you turn the key one position anti-clockwise from the 'all off' position? You should see tail-light (and any pilot light) illuminated; if you turn on the headlamp switch, that should be illuminated too.

If the bike has a standard ignition switch, check the different wires are attached to the correct terminals: Brown/Blue (from battery -ve) to terminal #1, White to terminal #2, Brown/Green to terminal #3. Original Lucas switches had terminal numbers pressed into the brown material beside each terminal; bigt Wassell Lucas and other pattern switches don't; facepalm however, if one of the terminals is a single spade, it's easy to work out the other three. smile

2. The contacts within the switch might be corroded. With a multi-meter set to Ohms (if not that word, a horseshoe-shaped symbol), connect one lead to terminal #1, the other lead as follows:-

. 'all off' - no continuity (high Ohms up to infinite) when connected to any other terminal;

. one click anti-clockwise - continuity (zero Ohms on an analogue meter, a few tenths of an Ohm on a digital) with terminal #3, no continuity with #2 or #4;

. one click clockwise (from 'all off') - continuity with terminal #2, no continuity with #3 or #4;

. two clicks clockwise - continuity with all terminals.

3. Set the meter to a Volts scale just above 12V, connect one meter lead to each battery terminal, note the meter reading, turn the ignition switch one click clockwise from 'all off'; leaving one meter lead attached to battery +ve, move the other meter lead to the White wire at each brake switch (if your bike has the front switch in the cable). You should see the same meter Volts reading as you did when both meter leads were connected to battery terminals. If you don't, the bike has a problem in the White wire(s) between ignition switch terminal #2 and the brake switch.

. If you aren't seeing any drop in Volts between battery and brake switch White wire(s), move the meter lead to the Brown wire on each/the switch, pull the front lever and/or press the rear lever (to connect the switch contacts) while watching the meter reading; again, if you see a difference in the meter reading from previous ones, the switch has a problem.

. Finally, go to the rear lamp, remove the lens and the bulb, identify the contact in the bottom of the bulb-holder that's the end of the Brown wire; carefully connect the meter lead (so whatever you use on the end of the meter lead doesn't touch anywhere else on the bulb-holder) and, while watching the meter reading, pull or press a brake lever - again, you're looking for the same Volts reading. If/when you see it, You have continuity from battery -ve to the end of the Brown wire in the rear lamp.

4. This leaves the 'grounding' - return from the bulb-holder to battery +ve. Part-way through '71, Lucas started supplying/Triumph started fitting rear lamps with a Red ground wire attached to a loop on the outside of the bulb holder; the other end of the wire should be attached in a Red-wires snap connector under the seat - deffo not somewhere half-arsed like a bolt on the rear lamp mounting or somesuch.

. If your bike's rear lamp doesn't have a Red wire (only Brown and Brown/Green (pattern Red and Black or something equally dumb facepalm ), most long-term reliable is fit one, alongside the existing two wires; ideally threaded into the lamp housing and attached to the bulb holder; if too difficult, attached under one of the nuts on the two 2BA-threaded studs that protrude through the lamp backing plate; other end of the new wire, as I say, connected into an existing Red wires snap connector under the seat.

Originally Posted by btour
Brake light
(btw, what is that bulb?)

confused It's a bog-standard twin-filament rear bulb. Originally 5W tail filament and 21W brake filament but a similar US bulb might be slightly different (6W and 23W respectively?).

Hth.

Regards,

#710908 - 10/08/17 8:52 pm Re: Tail light going off on advancing key. [Re: btour]  
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Id guess an incorrect connection at the switch. This is what I noted on the bulb last time:
Brake and Tail light : bulb 380 , 12V 21/5W BULB with BAY15d base (1157)

Funny I got stopped by a French cop Friday. He said my pilot light was not bright enough, let me go with main on though.


3D TV: A format that lost a format war without even having an opponent.
Bikes:
69 T120 on average (1967 rolling frame and 1971 Bonnie engine)
57 T110 on average (58 rolling frame - with 55 iron head engine)
#710914 - 10/08/17 9:27 pm Re: Tail light going off on advancing key. [Re: BrettF]  
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Hi Brett,

Originally Posted by BrettF
stopped by a French cop Friday. He said my pilot light was not bright enough, let me go with main on though.

I mentioned "Eagle Eye LED" in your thread on the TriumphRat CVV forum; the guy who put me on to 'em had just posted a thread on IKBA - "A65 Spitfire" - picturing the one the bike has fitted in the standard Lucas pilot hole. Or just search "eagle eye led" in Motorcycle Parts on eBay.co.uk

Regards,

#710923 - 10/08/17 10:16 pm Re: Tail light going off on advancing key. [Re: btour]  
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Stuart,


1. By "advance", you mean turning the key clockwise from the vertical 'all off' position? If so, what happens if you turn the key one position anti-clockwise from the 'all off' position? You should see tail-light (and any pilot light) illuminated; if you turn on the headlamp switch, that should be illuminated too.

When I turn it counter clockwise ( to the parking position) head light comes on but no tail light.

Advancing 1 click clockwise to run (ign) position tail light comes on, but I suspect it is the brake light, and the tail light or just brake light, because it is so bright. ie there is no separate brake light coming on.

One more click clockwise and ign and head light work, but no tail light no brake light.

All is grounded well with dedicated ground.

I assume to accomplish number 2 one has to disconnect the battery, or one will be shorting things out, or could. Is that correct?

I seem to remember that the switch for the rear brake can get stuck in on and cause something like this. There is some kinda loop to that. Making it essential to correct functioning it. Is that correct?


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
#710924 - 10/08/17 10:17 pm Re: Tail light going off on advancing key. [Re: btour]  
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Stuart,

"however, if one of the terminals is a single spade, it's easy to work out the other three. "

Please elaborate.

This is so frustrating. I had this stuff dialed in. Now I am back to an eight years ago problem, and I have forgotten. I am actually hoping it will rain. Everything hurts coming kneeling and lying and bending over to massage this thing. Now it is this close and chasing this problem. And the separate thread.

Last edited by btour; 10/08/17 10:27 pm.

Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
#710960 - 10/09/17 6:47 am Re: Tail light going off on advancing key. [Re: btour]  
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These 4 pos switches are prone to give grief. Provided you have your connections right, you my want to have a look at this:
http://www.nocnsw.org.au/technical/rebuild-lucas-ignition-switchtobetterthannew
I've done this with a lot of switches lately, it isn't hard and it really works.
I bought a new switch for my Trident 3 years ago and it started acting up this spring. Fixed it in an hour, no troubles since.
As is discussed in the article, the two "Bakelite" (or whatever) plates with the contacts on one thin plate and the other floating on top of it, is not very sturdy, allowing the contacts to shift slightly with the pull of the wiring on the spades. This leads to poor contact and corrosion over time. Gluing the plates together and then flattening the contacts cures this.

Good luck btour! I can feel your frustration!

#710977 - 10/09/17 12:16 pm Re: Tail light going off on advancing key. [Re: btour]  
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Hi Bob,

Originally Posted by btour
Advancing 1 click clockwise to run (ign) position tail light comes on, but I suspect it is the brake light, and the tail light or just brake light, because it is so bright. ie there is no separate brake light coming on.
I seem to remember that the switch for the rear brake can get stuck in on and cause something like this.

Well, yeah ... two of the problems causing incorrect functioning of the brake-light filament are the front brake switch jamming on and/or the rear lever switch not adjusted correctly.

Originally Posted by btour
When I turn it counter clockwise ( to the parking position) head light comes on but no tail light.
Advancing 1 click clockwise to run (ign) position tail light comes on, but I suspect it is the brake light, and the tail light or just brake light, because it is so bright. ie there is no separate brake light coming on.
One more click clockwise and ign and head light work, but no tail light no brake light.
All is grounded well with dedicated ground.

A fifth possibility I forgot to mention in my previous post is a simple faulty rear bulb. Try another twin-filament bulb.

Before you refit the tail-lamp lens, clarify your suspicion whether or not "tail light comes on" is the brake filament, tail filament or both. Thin filament is tail, thick filament is brake.

Have you actually checked, "All is grounded well with dedicated ground" using the 'Ohms' setting of a multi-meter, one meter lead connected to the rear lamp bulb-holder and the other meter lead connected to the battery +ve terminal?
Because the symptoms you describe could be the rear lamp "dedicated ground" not actually working: when "Advancing 1 click clockwise to run (ign) position tail light comes on", the tail filament is "grounding" through the brake filament; "One more click clockwise and ign and head light work, but no tail light no brake light" mean both rear lamp filaments are being supplied; without a separate continuous Red wires "ground" path all the way from rear lamp to battery +ve, neither bulb filament will 'work'.

And/or there's a problem in the Brown/Green wire between ignition switch and tail-lamp:-

. There are two Brown/Green wires into one female spade terminal; the female spade is attached to ignition switch terminal #3?

. If so, one Brown/Green supplies the tail-lamp, the other Brown/Green supplies the pilot lamp, speedo. 'n' tacho. lamps and the headlamp on/off twist-switch on the headlamp shell. A Blue wire runs from the twist-switch to the handlebar dipswitch, so turning the twist-switch turns off the headlamp?

Originally Posted by btour
I assume to accomplish number 2 one has to disconnect the battery, or one will be shorting things out,

'Fraid you can't use the Ohms setting of a meter to test a component attached to another battery; the meter uses its internal battery to establish a low-power circuit through whatever's being tested to measure the resistance. Btw, one reason you can get weird reading when testing Ohms is the meter battery is low or flat.

Originally Posted by btour
Originally Posted by Stuart
however, if one of the terminals is a single spade, it's easy to work out the other three.

Please elaborate.

http://www.britbike.com/forums/ubbthreads.php?ubb=showflat&Number=708190#Post708190; "L.A.B." posted a picture of the switch terminals numbered.

Hth.

Regards,

#710997 - 10/09/17 2:49 pm Re: Tail light going off on advancing key. [Re: Stuart]  
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Oh Good. Stuart you were correct. And thanks for the refresher.

I think I have found the problem if not the solution. There are two parts to the problem.

1) It was 3:00 in the morning when I put the spare bulb from my kit into the tail light assembly. I don't know why I had it there. Maybe if I had just turned it around I would have had a tail light but no brake light. It is very sturdily built, unlike the new ones. Anyway it had only a single filament. So I put in another.

2) Once running brake light was working, I found I did not have brake light, so I started wiggling brown wires. Indeed, the switch for the front brake is located in the cable. That switch is stuck on. Pulling "down" or out on the spade terminal for the brown wire, makes it work properly. That cable has been a problem since it was renewed. It fits too tightly. There is no room to loosen adjustment. The brake does function, but the switch, is tricky. I had forgotten this issue. I think I remember running down the street sending Morris code in gibberish. Might be dangerous in these days, since Homeland Security might suspect me. smile And the problem has melted the tail light lens, in the shape of the bottom of my back pack. smile Which is a testament to the orginal plastic. It is now deformed into a sculpture.

All the wires are really stiff in their insulation. That would be expected since they are now 46+ years old. Were does the time go? Only in a forward arrow, and much too fast when life is OK and much too slowly when it is horrible. (in that instance think of the line from an existentialist book, can't remember which one. "Because of the sun". Think of the sun at high noon in a desert, and it does not seem to move, just punish.

Any ideas on how to fix that switch? I have tried this great stuff from radio shack I bought decades ago. Almost out. Comes in a can with a little brush. It cleans great and seems to leave a lubricating film.


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
#711000 - 10/09/17 3:05 pm Re: Tail light going off on advancing key. [Re: btour]  
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Thank you Stein for that great link on the internals of the switch and how to improve.


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
#711123 - 10/10/17 7:33 pm Re: Tail light going off on advancing key. [Re: btour]  
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Stuart,

I am curious about the original situation. If as I discovered the brake light was on, on the first clockwise rotation of the key switch, then why would it not have remained on the next Clockwise rotation? Brake circuit active is brake circuit active I would think. But instead it went off.


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
#711143 - 10/10/17 8:58 pm Re: Tail light going off on advancing key. [Re: btour]  
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Hi Bob,

Originally Posted by btour
I am curious about the original situation. If as I discovered the brake light was on, on the first clockwise rotation of the key switch, then why would it not have remained on the next Clockwise rotation? Brake circuit active is brake circuit active I would think. But instead it went off.

"on the first clockwise rotation of the key switch", all White wires are energised, White wires supply the brake switches, front brake switch was stuck on, Brown wire and rear lamp brake filament supplied - i.e. one end of that filament was connected to battery -ve via the Brown wire, front brake switch, White wire, ignition switch and Brown/Blue wire.

Then I suspect the brake filament was 'grounding' through the Brown/Green wire - i.e. the other end of the brake filament was finding a path to battery +ve through the Brown/Green wire and its other connections (strange as it might seem, this isn't unusual, the turn signals idiot lamp works normally using the same principle).

However, when you made "the next Clockwise rotation", it connects Brown/Green to battery -ve through the ignition switch and Brown/Blue wire. So, the rear lamp had both wires (Brown and Brown/Green) connected to battery -ve and none to battery +ve - no complete circuit from battery -ve to battery +ve - so the brake filament went off.

For much the same reason, the bulb filament didn't come on when you turned the key anti-clockwise from 'all off'. This ignition position connects Brown/Green to Brown/Blue (and therefore battery -ve) but not the White wires (and therefore the Brown wire through the stuck front brake switch). So again, no complete circuit from battery -ve to battery +ve - so the brake filament didn't illuminate.

Hth. smile

Regards,

#711200 - 10/11/17 1:36 pm Re: Tail light going off on advancing key. [Re: btour]  
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Stuart, Thank you! I know this is much easier than it sounds. I think if I read what you posted 100 times it will become clearer. smile


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.

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