Hazards for relayed indicators

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Fingolfin
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Hazards for relayed indicators

Post by Fingolfin »

Evening folks,
I was told by Autosparks recently that hazard lights and combined brake/running and turn lights (that is, the kind of Minor with the eight-way relay) are mutually exclusive; you can't have hazards with the relay. I accepted that out of hand, because they're bound to know electrical stuff better than I.
Then I started thinking about it. There are a great lot of older and newer American cars, at least, that have the combined lights. Actually I think that setup is more common (at least for model years still using bulbs -- can't say the same about LEDs) on American cars than the separated bulb system. It is true that most older cars, including American ones, don't have hazards; but many more recent ones do have hazards and the combined bulb setup.

So why would Autosparks say it's impossible? If it's not, can anybody think of a way it could be done? I'd really like to have hazard lights.
The way to a man's heart may be making food, but the way to my heart is buying me car parts!
Come read about my Minor at An American Moggie.

Declan_Burns
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Re: Hazards for relayed indicators

Post by Declan_Burns »

Fingolfin,
I am not convinced you have been advised correctly.I have just converted my recently acquired Ex USA MG TD which has the same set-up- just the tail stop lamps which flash via the hazard warning which was already fitted after the car was imported by the previous owner. Hazards are mandatory here in Germany on all cars even if the original never had them! I retrofitted amber indicators-see photo below. The TD has the same 8 terminal indicator relay box and the brake light switch is connected to this relay at terminal 5. For the European system with separate amber indicators , the brake light switch needs to be wired separately and not via the 8 terminal relay box. You need to separate the brake light system from the indicating system. Relay box terminal 5 is then redundant.
Regards
Declan[frame]Image[/frame]


Regards
Declan
alex_holden
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Re: Hazards for relayed indicators

Post by alex_holden »

It is possible; I've done it on one of my cars. It took a couple of extra relays and some slightly complicated re-wiring. There are a few gotchas (eg. in one configuration I tried, pressing the brake pedal while the hazards were operating made the ignition pulse on and off! :oops: ). Unfortunately I haven't had time to draw a diagram of what I ended up with.
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Alex Holden - http://www.alexholden.net/
If it doesn't work, you're not hitting it with a big enough hammer.
Fingolfin
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Re: Hazards for relayed indicators

Post by Fingolfin »

Okay then. I had a sneaking suspicion it had to be possible somehow. :roll: I shall give this some deep thought...
The way to a man's heart may be making food, but the way to my heart is buying me car parts!
Come read about my Minor at An American Moggie.

bmcecosse
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Re: Hazards for relayed indicators

Post by bmcecosse »

As Alex explains - it is of course possible - just need a relay to separate the systems. Set up a hazard switch through an electronic unit into a double pole relay - then drive each side of the flashers from one pole of the relay. Simples!
Edit - if experiencing back feed problems, just drive the whole lot through a relay, and use a pole of that relay to isolate the normal flasher supply when the hazards are energised. Simples!!
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Fingolfin
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Re: Hazards for relayed indicators

Post by Fingolfin »

Hmm, that's some smart thinking there, BMC. And you're right, it's quite simple. All right -- I'll give that a shot when I'm doing up Mog's wiring in a few weeks -- and report back with success! 8)
The way to a man's heart may be making food, but the way to my heart is buying me car parts!
Come read about my Minor at An American Moggie.

beero
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Re: Hazards for relayed indicators

Post by beero »

Just wondering about flashing red lights as hazards. I would check with your friendly MOT man to see if it would pass.

bmcecosse
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Re: Hazards for relayed indicators

Post by bmcecosse »

Simply disable the system at MOT time.
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Fingolfin
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Re: Hazards for relayed indicators

Post by Fingolfin »

"Simply disable the system at MOT time"...oh, you guys are great! :lol: Our vehicle tests (in Missouri anyway) are much less stringent than your MOT seems to be. I guarantee the mechanic won't care. And if he or she does, then I'll do as BMC says. :wink:

I believe my parent's Chevrolet Blazer uses the red lights for hazards...though honestly I don't remember what it looked like when I last engaged them.
The way to a man's heart may be making food, but the way to my heart is buying me car parts!
Come read about my Minor at An American Moggie.

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