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Hi
I have installed LED indicators with matching flasher unit suitable for LED globes.
All indicators work perfectly until the motor is running than the indicators light up but won't flash.
Any idea what the problem is?
I haven't had this car on the road yet not sure if generator is all good yet.

Regards peter

Your first step would be to check your generator for output with a volt meter.

I suspect that the flasher requires a certain range of voltage to operate properly. I also suspect that the generator is not working so the voltage is lower on the running engine. That might be enough to have the flasher not flash. As advised by the Dog check the generator.

You might consider bench-testing it.

Hook up a couple 6v lights to a battery and add the flasher in the middle. Just attach simple alligator-lead clips to connect everything together. With a car battery used, it removes the other issues of voltage drop, etc.

Should be easy, and fairly quick to make sure that it all works. This will give you a really good idea of how many bulbs need to be connected in order to make the flasher work. Then you can go back to your car and test it all in your car's wiring - without the engine running.

Bill B

hi there,
LED's use almost no power and the flasher unit cannot see any voltage so does not activate.
I had the same problem with mine on my 35 chev std and had to purchase a gadget from the USA to introduce a "Load" into the circuit, so that the flasher unit would see voltage being used ( my version of the explanation).

Peter

Thank you for the replies,I will test the output on the weekend,and add load to the circuit.
Do you think polarising the generator would have any effect?

After you test the output on the generator and if you find that there is no output, then polarize then generator to see if that helps.

I just went ALL LED about 2 weeks ago in my '66 Corvette (naturally 12 volts). Prior to that I've been using LED stop lights for the past 4 years.

When I swapped out the 1157 tail lights for LED two years ago, I also purchased a new LED flasher. This is one which requires much less amperage in order to work. But after installing the new LED taillights, the original (factory) flasher still worked. So I left it alone. NOTE: It does blink just a little bit slower, not annoyingly so.

Now - two weeks ago I replaced my front running lights (ie. turn signals) for LEDs too. Now the original flasher doesn't work any longer. Time for a change.

OPTION 1: A lot of guys add a "load" back into their light circuit in order to get the flasher to work. Nothing wrong with this, but it kind of defeats the purpose of having LED bulbs by reducing the current draw. A simple way is to add an original filament bulb somewhere in the lighting circuit where the light is hidden. This loads up the system and it works again.

Another option is to buy a resistor which is specifically designed for this. Insert it anywhere in the (turn signal) line and it ups the circuit load, which causes the flasher to heat up the contacts and blink. If you're interested in this and can't find the resistor, let me know and I'll dig up the link.

OPTION 2: Replace the flasher with one designed specifically for low-load LED bulbs. THese are easy to find and Amazon has a bunch online. But -- something that I learned last week is that some 12v systems have the wiring to the flasher wired incorrectly. The polarity is reversed. Apparently this is so common that there is also for sale, a short "harness" that you can plug in which corrects this by reversing the wiring!!! Amazing.... This is for somebody who absolutely does NOT want to modify their OEM installation.

Now - what I also learned (and what I finally installed) is a special flasher unit that detects the polarity hookup and then automatically works with BOTH setups. It cost 2 or 3 dollars more, but it worked! Now I have everything hunky dory.

Good luck.

Bill B

Thank you all for the replies.
Basically you were all correct.
To summerise.
all 4 indicator globes were LED and connected to correct matching low currant flasher unit. All worked correctly when car not running.would not flash with car running just indicator light on no flash.
Changed to std globe in front indicator still only indicator on no flash.
Changed back to standard flasher can and all works again.
(that is LED's to rear indicators and standard globes to front indicators.)

To check this out further can you explain how to test generator out with meter please.
To Polarise the generator Is it as simple as connecting the battery input at the cutout across to the other connection at the cutout i think it is called the field terminal(chev 29)
Thanks for your help regards Peter

I still don't understand why the lights don't flash with low current (load) flasher when engine running.

To check the output of the generator. Measure the voltage at the connection from the wire coming out of the generator to the cut-out and a good ground. You may need to activate the generator by increasing to high idle. You should get ~ 7 volts. If not then polarize the generator by taking a wire from the battery positive terminal and striking it to the generator output wire. If the wiring is correct just jump around the cut-out or take the other cut-out wire and quickly touch the output wire.

Once polarized check the generator again.

....or you can simply lift the cover on the cutout, close the contacts for a moment using your finger, replace the cover, and you are done.

Good luck with it.

All the Best, Chip