Electrical gurus to the front of the line

[DJ]

Used to own a '67 triumph spitfire. Headlights were intermittent and wipers didn't work at all. But who cared. I was 20 years old, and who needs them anyway.
God I loved that car. Should never had sold it . Just a blast to drive!

 

[britman]

Starter relay (headlight/head light cut out) Triumph part number T2501705 is on its way. We will see shortly and hopefully on the way home at night. Thanks one and all for the suggestions and input. Also great to see Scott can still get PO'ed when defending the "Island across the Big Pond." I am sorry but that was a good one on the intermittent wipers.......

 

[Gregger]

Lucas didn't rely on voltage..... just smoke. You could see it escaping from time to time and when it did.... things happened.

 

[britman]

Installed the new relay this morning. Seems to have cured the problem, but only time will tell. Off for a ride in the 100 degree heat. Rule of thumb, it can't get too hot to ride, but it **** sure can get too cold...............

 

[DEcosse]

I can't dismiss 100% (never say never!) but I would be surprised if it was the starter relay for a couple of reasons:
1. The headlight circuit is through the N/C contact of the relay
2. Those contacts are now moving minimal current (150mA rather than the original 10A) so unlikely to be burned
3. Would not change if going from hi to lo (which was also stated as initiating the issue)

Since the EB relays themselves have been replaced fair to say those can be eliminated
So I would look at
1. The positive and negative connections to the battery
2. The Fuse Holder for the EB supply from battery positive (inspect the fuse and the holder for any sign of melting or simply oxidation)
3. Check the PosiTap connections - pull them apart to ensure wires not oxidized.
4. If you have the optional switch (controls low beam only) look at that (temporarily bypass for test)

However it's been a couple of weeks with no follow-up so it may well be resolved - if the starter relay fixed it, great, would be delighted to be 'wrong'

 

[tdragger]

Have you considered checking for corrosion on the high/low switch on the handlebar?

 

[DEcosse]

^ Another good suggestion

Here's a clue that will help narrow things: if it does not come on immediately when switching to 'high' does the high beam indicator come on immediately, or only when the headlights themselves come on?

 

[barbagris]

Hmmm - Whenever there is doubt there is no doubt.

And my golden rule of 'lectrics is - Until otherwise proven all faults are earth faults.
I had something similar where a relay was NOT earthing correctly.
As Ecosse has said elsewhere the Rocket frame is NOT the worlds best grounding system.

 

[JoseyR3Wales]

I can't dismiss 100% (never say never!) but I would be surprised if it was the starter relay for a couple of reasons:
1. The headlight circuit is through the N/C contact of the relay
2. Those contacts are now moving minimal current (150mA rather than the original 10A) so unlikely to be burned
3. Would not change if going from hi to lo (which was also stated as initiating the issue)

Since the EB relays themselves have been replaced fair to say those can be eliminated
So I would look at
1. The positive and negative connections to the battery
2. The Fuse Holder for the EB supply from battery positive (inspect the fuse and the holder for any sign of melting or simply oxidation)
3. Check the PosiTap connections - pull them apart to ensure wires not oxidized.
4. If you have the optional switch (controls low beam only) look at that (temporarily bypass for test)

However it's been a couple of weeks with no follow-up so it may well be resolved - if the starter relay fixed it, great, would be delighted to be 'wrong'

Being an old electrician, most of the time its a faulty component and that just takes some meter work or most likely poor connections from moisture invasion and vibration over time. DEcosse is a brilliant mind here. Enlarge your ground path cable as stock is barely large enough. Tighten every season, she's a BIG machine. Even the Space Shuttle failed to launch occasionally.

 

[barbagris]

Even the Space Shuttle failed to launch occasionally.

Not exactly a comforting comparison!