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Hazard Flashers

PostPosted: Wed Jan 20, 2021 6:16 pm
by fattogatto
Simple issue with way too many confusing answers in the forum. My 1967 British S3 came (at least to me) without emergency flashers. I have an extra switch (single pole/single throw) to use for this purpose.

Does anyone have any simple method of installing a flasher relay?

Assume wiring from hot side of ignition switch (or some other constant hot) through the switch to the flasher relay unit. Then wire to left and right turn signal wiring. Then, with ignition on and emergency switch off, all will work as normal. When emergency switch is turned on a flashing signal will go to all turn indicators.

Will there be any conflict if the emergency switch is turned on while turn indicators are working?

Also, I assume I'll need an older flasher unit for non-led lights.

Thanks

Re: Hazard Flashers

PostPosted: Wed Jan 20, 2021 6:43 pm
by HCA
Are you saying that the switch you have is not connected to anything? This is a basic method of adding emergency flashers to older cars - it should connect a green/white wire and a green/red wire. When the swich is thrown, and the indicator stalk is in either L or R position, all four lights will flash. Downside of this method is the flashing is slower.

To do the job properly, you will need to wire in a dedicated flasher relay that can use the same switch.

https://www.autoelectricsupplies.co.uk/ ... ategory/43

Re: Hazard Flashers

PostPosted: Wed Jan 20, 2021 8:01 pm
by fattogatto
That is correct. The switch is not connected to anything at the present time.

I plan to use a flasher unit.

Re: Hazard Flashers

PostPosted: Wed Jan 20, 2021 8:29 pm
by davidj
I don't think it is possible to wire hazards with the switch you have because all the wiring circuits I have seen disconnect the flasher circuit when the switch is activated. You also want the hazards to work with the ignition off.

I used a lucas toggle switch many years ago but it was a three position one, top, indicators work as normal, middle no indicators and bottom hazards. Unfortunately I cannot remember the circuit!

However, I have just installed a hazard switch in a hole in my dashboard conveniently left by a previous owner. In this case, I used one of the triumph pull switches (ex spitfire etc) which looks period and flashes, so you don't need to have any additional dash lights. They are available on ebay and this is how I wired it.

Re: Hazard Flashers

PostPosted: Wed Jan 20, 2021 8:32 pm
by oldelanman
The site linked to above also has a wiring diagram which you may find helpful.....

https://autoelectricsupplies.co.uk/file ... iagram.jpg

Re: Hazard Flashers

PostPosted: Mon Jan 25, 2021 4:28 pm
by stugilmour
The diagram Roger posted above looks like a reasonable starting point.

You could use two micro relays to replace the double throw double pole switch shown. Use your simple dash switch to trigger the two relays. I had to do something similar when rewiring my Plus 2 as the matching stock hazard switch did not have enough terminals to accommodate my loom, which used a more modern single flasher relay setup for both the indicators and the flashers.

Rather than picking up the main power for the emergency flashers from the hot side of the ignition switch (Brown - Hot at all times, Unfused) you may prefer to pick up a fused power supply (Purple - Hot at all times, fused).

Here is a link to the micro relays on the same site

https://www.autoelectricsupplies.co.uk/product_list/194

HTH