Video: LED Installation and Common Issues

LED lights use Light Emitting Diodes to produce light.

Most of us already know…
1 LED bulbs can be significantly brighter than conventional bulbs.
2 LED bulbs consume a tiny fraction of the electricity a conventional bulb consumes. That’s a big help when you are sitting in traffic with several demands on your electrical system and only a low-powered generator or alternator (at idle speed) trying to feed everything.
3 LED bulbs come on and go off with stunning speed and brilliance which helps our stop lamps and turn signals to get people’s attention.

The purpose of this presentation is to focus on some common questions concerning LED’s and how to install LED’s in your Classic British car.

First. LED lamps are polarity sensitive. The overwhelming polarity bias for cars in the world today is toward negative ground. For that reason, LED lamps, to date, are only for negative ground cars. Here at Moss we’re working to add positive ground LED’s to our offerings, but as of the time this video is being produced, positive ground LED’s are still only on the wish list.
It’s the same problem we face when looking for positive ground radios. Positive ground radios just aren’t out there.
If your car is positive ground (positive earth) and you want LED’s, you either have to convert the car to negative ground, or give up the LED idea.

Next, LED’s call for using an electronic flasher. Why?
Traditional flashers rely on the current flowing through them to heat a bimetallic strip of metal. The metal changes shape from the heat and that causes the current to blink off and on.
A video that lets you see the internal parts of a traditional flasher, while working, is available on YouTube. Go to YouTube. In the search field type in “Moss Motors Turn Signals.”

This technician recently tested a conventional tail light bulb and found it consumed about 2 amps. An LED replacement for that bulb was installed. It consumed about 0.2 amps. (1/10 the power demand.) A flasher that’s designed to operate using the heat from the current passing through it will simply not work with so little current going to the LED lamps.

The solution is to use a flasher that does not rely on the heat from current-flow to operate. That’s where Electronic flashers come to center stage. Electronic flashers sense almost any demand for current, and then the flasher turns the current off and on using micro-switches. That’s much smarter than using current to make heat to operate a flasher.  Since electronic flashers are not dependant on the current demand of the bulbs… they work well even when the current draw varies. If a conventional bulb in your car fails (less draw), or you add a trailer to your car (more draw), in most cases, the electronic flasher will work as it should.

We here at Moss found that even then, some electronic flashers are not sensitive enough to detect the very small amount of current that LEDs might demand. The answer is to use an electronic flasher that is engineered to be sensitive enough to detect even the tiny current demands of a system using LEDs. We have those flashers here.
LED Installation & Common Issues
The subject of ballasts is complicated by the fact that many of our Classic British Cars need a pair of ballasts, and many of our Classic Cars don’t. So your car will need two, or your car won’t need any.
In almost every occasion the issue is hidden in the way the turn signal indicator light is wired.

Moss Tech Services


'Video: LED Installation and Common Issues' have 5 comments

  1. April 29, 2013 @ 5:36 pm Dick Wachtman

    Since installing LED lamps for turn and brake lights including an electronic flasher in my ’80 B, the 4 way emergancy flashers will not work. I expect this is because I have to add an electronic flasher for them. I haven’t seen any mention of this anywhere.


  2. May 1, 2013 @ 9:25 am carlbergs

    It is very likely you will also require an electronic flasher for the hazards. We are working up some information on this.
    Lot’s have people have left their car with the flashers on only to return an hour or two later to a dead battery.
    LED hazard lights will last many times longer because they draw so little power and should leave you with enough power to crank it up on return even after several hours.


  3. June 15, 2013 @ 12:10 am John Cozins

    Your Moss Motor technical articles are excellent and always very helpful.
    However, I have often wondered why Moss Motors do not offer LED lighting conversion kits for at least the more popular models of older British sports cars. Kits that include all the necessary matched components to make the whole thing work properly, (flasher units matched to the LED’s as well as any further bits that may be necessary to stop current feeding back to where it is not wanted.


  4. August 8, 2013 @ 2:14 am okledlights

    Most people prefer to buy LED lights in comparison of traditional bulbs because led lights produce less heat and saves energy. LED lights are cost effective and energy efficient diode. The installation of light emitting diodes is also very easy.I once buy from OKLEDLIGHTS (dot) COM is nice .


  5. January 11, 2018 @ 7:40 am John Huber

    I bought a pair of headlights for my 1963 MGB and was told they have LED bulbs. Any concerns or things I should look out for ?
    John Huber


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