Strange Signal Light Problem

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steveyacht

steveyacht

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I have a 73, 750 roadster that I am having a very strange problem with my signal lights. I obtained LED replacements for the signals light lamps,from a company that specializes in British spares. (they have been great). I am working with them also.
I replaced the rear two, checked their operation, which was perfect, then moved to the front. When I checked them after the installation, all four lights came on, steady, no blinking, without the signal switch being activated.
So, I removed the new LED's and replaced the fronts with the old bulbs, again, they worked as normal with the rears being LED and the fronts being standard bulbs.
Thought it may be something with the Flasher as I had an HD unit in that was rated up to six bulbs. Replaced it with a "normal" flasher rated for four bulbs.
Tried it again. Still same problem.
I would prefer to replace all with LED's, as they really are SO much brighter, but I can deal with only two if I can't figure this out.

Thanks in advance for all of your help.
 
I had a short inside one of the tubes the lights mount to. IIRC, the light on that side wouldn't work but turning it on the other side would light up. Check for internal shorts.
 
The flash indicator lamp on your headlight shell is wired between the left and right indicators. Basically it works by putting a small current through the non-flashing lamps. The fix for that is wiring in a couple diodes that isolate the warning light. And you will need a new flasher that works with LED's.
 
The new flasher might cure the issue. And I think the LED-rated flashers will still work with standard bulbs, if it comes to that.
 
Danno said:
The new flasher might cure the issue. And I think the LED-rated flashers will still work with standard bulbs, if it comes to that.
Click to expand...

The flasher won't cure the problem of all 4 lights coming on. The warning light connects both sides together - you either have to remove it or decouple it with diodes.
 
Agreed that the "tell-tale" warning lamp is the cause of the all-on LED syndrome. Get or make up a "tweaker" pair of diodes as described in the links previously posted. You will also need an LED compatible flasher unit as the much lower load from your LED indicators will cause very fast flashing with a regular incandescent flasher unit.

One thought, would using a "polarity insensitive" (ie works with both positive and negative ground sockets) warning LED in place of the incandescent warning lamp negate the need for a tweaker diode pair?
 
Tornado said:
Agreed that the "tell-tale" warning lamp is the cause of the all-on LED syndrome. Get or make up a "tweaker" pair of diodes as described in the links previously posted. You will also need an LED compatible flasher unit as the much lower load from your LED indicators will cause very fast flashing with a regular incandescent flasher unit.
Click to expand...

Very slow... or not at all. Conventional flashers use a bimetalic strip that heats up from bulb current and opens... then closes when it cools. LEDs don't draw enough current to make them open.

One thought, would using a "polarity insensitive" (ie works with both positive and negative ground sockets) warning LED in place of the incandescent warning lamp negate the need for a tweaker diode pair?
Click to expand...

If the LED indicator was bi-directional (polarity wise) and draws 10 times less current than the blinkers... maybe. That's how the stock system works - the "off" side is actually being powered through the warning light.
 
maylar said:
Very slow... or not at all. Conventional flashers use a bimetalic strip that heats up from bulb current and opens... then closes when it cools. LEDs don't draw enough current to make them open.



If the LED indicator was bi-directional (polarity wise) and draws 10 times less current than the blinkers... maybe. That's how the stock system works - the "off" side is actually being powered through the warning light.
Click to expand...
I'm thinking flash rate increases b/c when a traditional automotive incandescent bulb burns out, the flasher rate goes very fast and is a good way to know you've got a blown bulb. So an LED should appear like a burned out incandescent to the standard flasher, no?

For a non-polar LED warning lamp, don't they just have a built in "tweaker" diode pair circuit so they don't care which way the current flows into the contacts?
 
OK, I found this on the SuperBright LED website on how to solve hyperflashing of LED turnsignals:

"
Although the reduced draw of LEDs has advantages, replacement of turn signal bulbs with LEDS will cause what is called hyperflashing. Hyperflashing is when the turn signals blink faster than your stock incandescent bulbs did. This happens because your new LED bulbs draw such little power that your turn signal relay sees the bulbs as being out.

There are two strategies you can use to fix this issue:
Installing an LED flasher module specifically designed for LED bulbs. This is the easiest method for f
Strange Signal Light Problem
ixing hyperflashing. These modules are economically priced and are usually simple to install. In most cases, these flasher units are little circular or square boxes with metal prongs sticking out one side that simply plug into where your stock flasher went. Our LED flashers function with both LED and incandescent bulbs, so even if you have LED turn signals in the back and incandescent bulbs still in the front, you can use our LED flasher modules with no problems. Before you order, compare the pin diagram of the stock flasher with the pin diagram of our flashers on our website.

Installing a load resistor kit. Unlike plug-and-play LED flasher modules, load resistor kits require some wiring
Strange Signal Light Problem
to install. Through the use of a load resistor kit (pictured right), LED bulb blinking can be slowed down to a normal rate. These resistors are to be installed in parallel (tied to positive and negative) for each LED bulb. A detailed printable installation guide can be downloaded here: How to Install an LED Load Resistor"



https://www.superbrightleds.com/blog/led-turn-signals-blinking-too-fast-hyperflashing/275/
 
You need a 2 wire LED compatible flasher. I got one from an auto parts store but don't know if it'd work positive ground.

Resistors are silly IMO - they make the old flasher work by adding more current.
 
maylar said:
The flasher won't cure the problem of all 4 lights coming on. The warning light connects both sides together - you either have to remove it or decouple it with diodes.
Click to expand...
What is the reason this occurs with LEDs and not with the standard incandescents?
 
Danno said:
What is the reason this occurs with LEDs and not with the standard incandescents?
Click to expand...

The warning light takes far less current than incandescent bulbs, not enough to light them. But compared to LEDs it's significant. Actually, the incandescents are on too... but very very dimly.
 
I tested the Titanic's signals in a dark garage and saw no evidence (when everything was as it should be) of the opposite sides lighting up, even dimly.
Have you seen this phenomena for yourself?
I will test again (in the dark) to see if I can spot it.
 
Danno said:
I tested the Titanic's signals in a dark garage and saw no evidence (when everything was as it should be) of the opposite sides lighting up, even dimly.
Have you seen this phenomena for yourself?
I will test again (in the dark) to see if I can spot it.
Click to expand...

No, it's just a technical detail. The warning light bulb is only 2 watts, the blinker is 21 watts. The small amount of current through the warning bulb won't be noticed in the blinkers - but it is there. With LED's it's a whole different story.

read: very very dimly as unnoticeable.
 
maylar said:
The flash indicator lamp on your headlight shell is wired between the left and right indicators. Basically it works by putting a small current through the non-flashing lamps. The fix for that is wiring in a couple diodes that isolate the warning light. And you will need a new flasher that works with LED's.
Click to expand...

Thank you all for getting back to me.... I do have a couple of questions and an additional bit of information. Both flashers I used work fine with only two LED replacement bulbs installed. No fast flashing, works same way it did with incandescent bulbs. Only when I install all four LED bulbs is there a problem. Hope this clarifies that issue. I Should also add that the bulbs I purchased were for positive ground systems and were purchased from a company that specializes in British Motorcycles. They have been helping also.... so far, no definitive solutions. https://www.classicbritishspares.com/

Now, being as I am totally out of my element when it comes some electrical work, can anyone show me what diodes to use and explain how I should wire these into the system? I am willing to try pretty much anything in order to get brighter lights.

Thank you all for your help and assistance, I really do appreciate it.
 
Traditional flashers work by sensing bulb current and breaking/making contact. With 2 bulbs and 2 LED's there's still enough current to make them work. With 4 LED's the flasher doesn't have enough load to flash, and your warning light will make all 4 of them light.

If electrical stuff isn't your thing then pointing you to an electronics supplier for diodes is probably a bad idea. Simplest solution is Goffy's "tweakers" as posted by LAB -

http://www.norbsa02.freeuk.com/GoffyLEDIndicators.htm (near the bottom of the page)
 
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