TR2/3/3A Positive-ground LED lights

[RonR]

Folks,

I installed positive-ground LED turn signal and brake lights, and a positive-ground electronic flasher in my positive-ground TR3A.

While everything seems to work, the turn signal lights flicker when the engine is running. It is so minimal, one has to look real close in daylight to see the flicker.
Is this normal?
If it is not normal, could it be possible that the vendor sent me one or more negative-ground light bulbs, or a negative-ground flasher unit?

I ask, because after driving the car a little over an hour (82 miles) on Christmas Eve, the car started missing and I had to be towed back home.

Thanks.

 

[Geo Hahn]

A negative ground LED would do nothing if installed on a positive ground car - the diode would prevent it from lighting.

I have no experience with negative ground flashers so cannot help there - but I doubt your miss is related to the LEDs. I'd start by checking all the ignition components. A methodical thorough approach should fine the culprit. If the miss only comes on after an hour's drive then the coil would be high on my list of suspects.

 

[RonR]

Thanks for your reply, Geo.

The coil was replaced earlier this summer, as well as having the distributor rebuilt by Advance Distributors.

I check all electrical connections and everything was tight, including the distributor mounting, telling me that the point gap and timing had not changed.

Regardless, I reset the points and timing, which at the moment, seems to have solved the missing issue.
However, I am not convinced that another long drive will be trouble free.

 

[Deleted member 8987]

Generator or alternator?
Alternator, if you have diodes going or gone, can still charge but can inject a bit of reverse voltage, enough to make LED's flicker. BTDT.

A lot of the LED's I have been researching have bridge rectumfriers built in, making polarity immaterial. Low voltages can cause misfire, too.

Check you charging system.

 

[RonR]

Generator, which is functioning properly.
LEDs were purchased from LiteZupp

 

[TR3driver]

I don't know about LiteZupp specifically, but I've bought several LEDs lately where the instructions said they were polarity sensitive, but the bulbs I received worked equally well either way.

The flickering I think is probably a slight electrical leak , probably at the control head. There should be no other connection to the turn filaments; and the flashers normal state is passing current, so it can't cause them to flash unless the control head completes the circuit.


But I agree with Geo, that doesn't have anything to do with your running problem.

 

[RonR]

Thanks, GP.

I did remove the flasher unit to see if that would stop the flickering, and as you noted, it did not.

Based on your suggestion of the control head, I wonder if the ground is insufficient.
The horn does work.
However, as I recall, the control head is grounded either through the three set screws that secure it in place, or through the control head back plate hitting the far inside of the steering wheel hub. I believe I had to shim out the control head at the back plate to get the three set screws to rub tight enough against the control head to hold it in-place. I used aluminum tape, but certainly the adhesive side would not properly ground the control head if the ground is by the back plate touching the inside of the hub.

FYI: non-adjustable steering wheel

 

[TR3driver]

The ground at the control head is only for the horn circuit. The turn signals ground only at the bulbs and possibly the flasher (for an LED flasher, stock flasher isn't grounded either).

 

[RonR]

Thanks, Randall.

Grounding for the front turn signal lights appears to be through the mounting screws, through the aluminum grill, through the screws securing the aluminum grill, and then eventually to the remainder of the grounding system.

With the engine running and the light switch off, what could be the possible source, or path, of electricity to cause the turn signals lights to flicker? This was not an issue with incandescent bulbs.

Ron

 

[TR3driver]

Actually, the front lamps should have a ground wire that runs up to a clip behind the horns.

By "leak", I mean some path that is not normally a wire or connection, fairly high resistance but enough that, apparently, it lets the voltage on the LEDs build up slowly until it's high enough for them to conduct briefly. Hence the flicker. Incandescent bulbs require a lot more current before they will light at all, plus they start to conduct as soon as the voltage rises above zero. LEDs on the other hand, don't start to conduct until there is around 1 volt applied, and will make light if there is any current at all.

It's hard to say just where you leak is, but one possibility is the control head; either a buildup of slightly conductive dirt, or the surface of the bakelite has oxidized, or there could be an errant wire strand. Could be somewhere else too.

You've already tried disconnecting the flasher; I might try disconnecting the horn fuse at the same time. Doing both of those should kill all power going into the control head.

But honestly, I would be more worried about why it wouldn't run. A barely visible flicker of the turn signals seems like a minor problem, and might even be an advantage if it causes other drivers to notice you

 

[sp53]

I do not know squat about LEDs, but the front lights are running lights and flashers together, so that if the running lights are on the flasher is just a little brighter. If I remember correct they are double bulb filaments. You could have the 2 wires hooked up wrong at the pigtail and are getting the running lights for the flasher and the flasher for the running lights, just flip the wires around where they plug in. In addition, you could have more than one problem. Might even be a weak battery or ground with the battery or poor body tub grounding, loose fan belt, weak generator, shorting coil, some of the coils are real crap. The car shut down in the day time with no headlights or heater or wipers? I always purchase as strong of battery as they have, I think 700 amps or something like that—that way the car can run off of the battery some if I understand how the regulator works.

steve

 

[RonR]

Hi Randall.

I thought the flickering LED lights may have been related to the engine missing because I never noticed the flickering lights until I arrived home via a tow truck and the car was backing down to my garage with the engine running and the lights off.

As I stated earlier, I now have the engine running without missing, but I am not confident I really did anything as a long term solution, since everything related to the ignition system was tight and unchanged from the between the engine running perfectly to it starting to miss. I even checked the new distributor cap for cracks. I was on an instate driving around 80 mph when it started missing after 82 smooth miles. Essentially everything is new or rebuilt, with less than 3000 miles on the engine. Over Thanksgiving, I drove it 400 miles round trip without any problems.

Tomorrow will be warmer here, near 40 degrees, so maybe I will take the car on a long drive and see what happens. After all, AAA is available on Sundays, but perhaps a bit slower.

Ron

 

[DavidApp]

Have you checked the ground point for the front flashers. Clean the body under the connection clip etc.

David

 

[Sarastro]

You might have a bad connection somewhere. If it's in the lighting circuit, it could cause the lights to flicker but would have no effect on an engine miss. However, if it is somewhere around the battery or charging system, it could cause both. I understand that the ignition wiring is tight, but what about the wiring between the battery and the ignition, including the switch, its connections, the battery and regulator connections, and so on? Also, a connection can be tight but not clean.

First step should be jiggling any relevant connection you can get your hands on. That should identify a bad connection.

Keep in mind that LEDs respond to voltage changes much faster than incandescent lamps. The voltage in these cars' electrical systems has a lot of noise (i.e., voltage spikes and fluctuations) and what you're seeing with the LEDs, especially if the flickering is very slight, might just be normal.