LED Flasher Lamps

[greyV8pete]

One of the jobs on my endless “to do” list for my Hunter this winter is to fit the LED flasher lamps that I bought at Donington a couple of years ago.

In order to avoid having a separate resistor in each feed wire I also bought a replacement plug-in relay for my Mondeo type steering wheel switch console, to suit the low current LED lamps. So in theory the turn indicators should work fine.

However I am wondering does anyone know what controls the hazard flasher circuit? Is it a separate relay designed to carry the 4 x 21w load? If so will it also need additional resistor in the circuit to make it work with the LED lamps? If it uses the same “new LED” relay will it flash all four LED lamps ok?

Maybe I just need to abandon the dedicated “LED type” flasher relay and use the series resistors in the lamps after all?

Anyone any ideas? Peter.

[andyf]

Re: LED Flasher Lamps

I would expect it to work fine as the dedicated led flasher relays are not load dependent.

[stevejgreen]

Re: LED Flasher Lamps

I would expect it to work fine as the dedicated led flasher relays are not load dependent.

As technology worked away from thermal devices, so solid state, that were not load dependant, became more common.
Just where the donor (presumably Sierra) fell in that historical line fell, I don't know.
My guess is, give it a try.

[keith_h]

Re: LED Flasher Lamps

For what it's worth, 18 years ago when I took my YKC Roadster to get its very first MOT (so that the DVLC would register it), it failed because the indicator flash rate was too fast. The MOT chappy told me that the Sierra electrics had a system that would monitor the current draw to the indicator circuit and if it was too low it would double the flash rate on the basis that it assumed one or more of the bulbs had failed. i.e. it was a crude warning system. The reason it was flashing too fast was that I had fitted very nice chrome bullet lamp holders on the front wings and the bulbs that fitted in them were only 4w instead of the 21w the system was expecting. Because I knew the owner of the garage I asked him if he had two 21w bulb holders in his stores and he let me loose in there to look. I found some and quickly fitted them (hanging down in the engine compartment) in series with the 4w wing top lamps.The MOT chappy was now a happy chappy as the rate was now acceptable and I came away with my MOT certificate. It was one of those jobs that I kept meaning to do but after 18 years and an engine bay that flashes at night whenever I use my indicators it has become an 'if it aint broke don't fix it" job

[greyV8pete]

Re: LED Flasher Lamps

Many thanks to all for the interesting and useful feedback. I had to smile at Keith’s fix. It must make the hot hatch lads with the neons underneath the car look twice!

I checked the new relay today and the markings on the side read “Electronic LED Flasher 12 V MAX 30W”. This would cope with 2x LED lights plus 1x5w side repeater. However with the existing bulbs and hazard switch operating, giving 4x21w + 2x5w repeater lamps, a total of 94w the new flasher unit won’t be able to carry the load without switching through a relay.

I have checked this evening and both the indicator switch and the hazard switch seem to activate a “click clack” relay noise from the same place inside the column console! That suggests to me that the flasher unit is supplying a timed pulse to a separate relay. That also suggests that maybe it would do that no matter what the bulb wattage / loading is?

Tomorrow I will try removing one bulb to see what happens to the flash rate and also check the same after temporarily wiring the new LED lamps to the existing circuit.

Peter.

[greyV8pete]

Re: LED Flasher Lamps

...... However with the existing bulbs and hazard switch operating, giving 4x21w + 2x5w repeater lamps, a total of 94w the new flasher unit won’t be able to carry the load without switching through a relay.

Doh! On reading my last post again after refreshing my brain I realise that this sentence is irrelevant as, after the conversion, the hazards will be flashing 4xLEDs and 2x5w side repeaters which should be well within the 30w rating of the LED flasher. I will still do the checks though. Peter.

[greyV8pete]

Re: LED Flasher Lamps

I tried removing one indicator bulb today and the flash rate became very fast, so the Mondeo set up is still load dependant. Due to this I didn’t bother with trying one of the new LED lamps as the minimal current drain is bound to give the same result.

So it’s back to "Plan A" and fit all the new LED lamps and the LED flasher unit at the same time. As that needs the rear light clusters redesigning a bit to accept the new lamps the job is waiting for a round tuit. Peter.