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Discussion Starter #1
the brake light still works but the tail light stopped. using an LED from Common-Motor and it checks out in my Harley. Tried a regular bulb and it doesnt work either.

pulled the tail light housing and the wires at fender and reconnected everything to make sure they were connected well

still nothing

correct me if I am wrong but the only wire to the tail light (not the brake light) ruds directly from the ignition switch? unless the 1973 K5 model is different from the k4?

all other lights work and the tail light did work a few days ago...

thoughts?
thanks
Robert
 

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Green/Yellow is the brake light wire. Systematically check continuity of these wires/connectors from the brake light


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Discussion Starter #3
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not the brake light - the tail light. brake light works, but I can guess the other wire (orange?) is the tail light then...

couldnt find a wiring diagram on here - tried at least 15 links that were all dead
 

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Brown wire is taillight, the orange is a signal light as is the light blue.
Sometimes there are also bullet connectors located inside the taillight housing pocket that the rear light is mounted too. If you have these did you check them? They are prone to getting corrosion, since they are more exposed to the elements being located in behind the licence plate.

The three key wires for you are
brown- running light
green and yellow- brake light
dark green- ground

Solid orange-signal used both front and rear
Solid light blue- signal used both front and rear.
The fronts will usually have a dual filiment bulb, so the addition wires are both light blue with a white stripe and orange with a white strip and these are the running lights for the front.
 

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That’s the running light portion of the dual-filament on the bulb. You said that it worked in another bike, so there’s a strong chance that your running light circuit is faulty.

According to the ‘73 wiring diagram, it’s a brownish wire connecting directly to the key ignition switch

Clean your connectors real well. Stick a multimeter between the connection of the Brown at ignition to the one at the tail light to check for continuity. You can also check for voltage of the tail light circuit at the switch. Have you also tried turning the key to the TL2 “parking light” position? Does the light come on then? If so, something is up with the TL1 on the key ignition. Perhaps a rebuild or replacement may be in order.


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Discussion Starter #7
thanks for the diagram! and correcting my thinking on the colour of the wires. I must have been seeing teh brown as orange in the dark with only a trouble light. I knew the blue and light orange wires were for teh signals as they obviously wne tot teh signal stalks at back and side from the portrective sleev at front fo the rear fender. When I went back out after the rain stopped, I put the tail light lens back on and took the bike off the charger - AND the tail light worked!?! wondering if the battery was too low to get power to the light? seems unlikely as the headlight was working and the signals were working

I did take the tail light housing off the back and pulled and reconnected the bullet connectors as well as at the front of the fender where it goes into a large protective sleeve

got me to thinking about running lights - the front signals dont have them and it seems like it would be a good idea to have at front and back - easier to see....

this bike is for my 16 year old and I want him as visible as possible.

on my way home the other night, as I rode it to sort out a carb issue, popping at right exhaust and idle issue, I was almost rear-ended by a car not wanting to stop as the traffic light turned amber and then red, so I moved forward, putting me into the interesection across teh cross walk and slightly blocking the adjacent traffic so I finshed making the left hand turn and got snapped by a red light camera! I have never been ticketed with a moving violation in 27 years of riding. I have been rear ended by a car in a similar situation so was trying to avoid that again - guess I am going to court to fight it now....
 

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In Ontario it is illegal to run anything other than red rear lights as running lights on the back, as I had the same thought as you. I also considered the dual filiment socket to the rear signal lights. I checked the MTO first and that is what I found out.
That being said it is highly unlikely a cop would pull you over, or even know that section of the traffic act.
You fixed the issue by cleaning the bullet connectors as suggested, since more than once I have encountered the same issue on the restorations I have done.
I would highly suggest going through every connection and cleaning them. The corrosion causes voltage drops throughout the system and could end up stranding your son at some point.
 
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Discussion Starter #9
finally found the tail light problem! was in process of removing ignition switch as I found that the tail light housing section of wires had continuity so it must either be in the switch or the main harness; I followed the switch wire to a brown plastic plug to the main harness and when I pulled the rubber casing off and took the plug apart to check continuity there, I noticed the brown wire going to main harness was loose in housing of brown plastic and when pushed together, the wire would be pushed out enough to cause intermittent (mostly failed) connection! I pushed the brown wire in with needle nose pliers and checked that it was firmly connecting with its counterpart from the switch and it seemed good so put the rubber housing back over the plug and all is right in the world now! LOL (well at least in the tail light working department)

thanks for the help

next question: anyone ever press in new float bowl over flow tubes? fi so how and where do you get them?
 
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